Pk1 05 pavement by ha szk as080922 in

DESCRIPTION

This project involves the supply, processing, hauling, spreading, watering, and compacting of graded aggregates on a prepped surface, as outlined in the Drawings or as directed by the Engineer Processing may include essential operations such as crushing, screening, separation, and blending to ensure the material meets the specifications outlined in this section.

MATERIAL REQUIREMENTS

Reference Standards

1 Construction and approval methods on grade aggregate foundation in highway pavement 22TCN334-06

2 Testing procedure on definition of compaction of road foundation and embankment by sand cone method 22TCN346-06

3 Procedures of soil and macadam compaction in laboratory 22TCN333-06

4 Testing procedures on definition of CBR value for soil and macadam in laboratory 22TCN332-06

5 Determining the Liquid Limit of Soils AASHTO T89

6 Determining the Plastic Limit and Plasticity Index of

7 Moisture Density Relations of Soils using a 4.54 kg

Rammer and a 457 mm Drop AASHTO T180

8 Soundness of Aggregate by use of Sodium or

9 Abrasivity Los-Angeles of aggregate (LA), % 22TCN318-04

Material Sources

All materials must be tested and approved by the Engineer before use by the Contractor The Contractor is required to inform the Engineer of the proposed sources of materials prior to their delivery to the Site and must secure approval based on the specifications outlined If a proposed material source fails to meet the specified requirements, the Contractor must provide alternative materials for the Engineer's approval Additionally, materials produced through commercial manufacturing processes must include the manufacturer's certification and accompanying test report.

GENERAL SPECIFICATIONS 05100 3 of 54 that the materials comply with the Specification requirements The Engineer’s approval of a source does not imply that all the materials from that source are approved.

2.3 Storage Mixing and Hauling Material a) Materials shall be so stored and handled as to assure the preservation of their Quality and fitness for construction Materials, even though approved before storage or handling, might again be inspected and tested prior to use Stored material shall be located to facilitate prompt inspection. b) Handling and stockpiling of aggregates shall be to the approval of the Engineer, and at all times be such as to eliminate segregation of the various sizes and contamination. c) Aggregate stockpiles for base course and subbase shall be protected from rain to prevent saturation of the aggregates which would result in a reduction in the Quality of the placed material or adversely affect the placement of the material d) Where materials of different size are to be blended to meet the gradation, such blending shall be as directed by the Engineer and shall be accomplished prior to delivery to the roadway Mixing of separate materials on the roadway by motor grader will not be permitted by the Engineer.

All materials that fail to meet the specifications outlined in this section will be promptly rejected and must be removed from the construction site at the Contractor's expense, without any time extensions for delays caused by this issue If defects in unacceptable materials can be rectified, they shall not be utilized until successful test results are received and approved by the Engineer.

2.5 Aggregate Subbase Material Requirements a) The aggregate for subbase shall consist of hard, durable particles or fragments of crushed stone, crushed slag, or crushed or natural gravel and filler of natural or crushed sand or other finely divided mineral matter The composite material shall be free from vegetable matter and lumps or balls of clay, and shall be of such nature that it can be compacted readily to form a firm and stable subbase. b) Aggregate Subbase Material shall be in compliance with requirements set forth in Tables Nos 1, 2 and 3.

Aggregate with Dmax = 37.5mm is appropriate with Subbase;

Aggregate with Dmax = 25mm is appropriate with Base;

Aggregate with Dmax = 19mm is appropriate with leveling and strengthening existing pavement structure in rehabilitation of road.

Table 1 Granular Composition of Aggregate

Dmax 37.5mm Dmax 25mm Dmax 19mm

Properties Required limit Test Method

1 Granular component Specified in table 1 (Dmax 37.5mm)

2 Los-Angeles wear of aggregate (LA), % < 40 22TCN318-04

3 Soaked CBR at K100 density, in 96 hours, % ≥ 35 22TCN332-06

5 PP index = Plasticity Index (Ip), % < 6 AASHTO T90-02

6 PP Index = Plasticity Index Ip x % material passing sieve 0.075mm < 60

Percent by weight of aggregate with diamond or flattened shapes,

22TCN333-06(method II-D)(AASHTO T191)GENERAL SPECIFICATIONS 05100 5 of 54

When utilizing crushed gravel, it is essential that at least 50% of the particles retained on the No 4 sieve possess a minimum of one fractured face Additionally, the liquid limit and plastic limit are established through testing the material that passes through a 0.425 mm sieve.

(**) Diamond / flattened shape are the one having thickness or width ≤1/3 its length:

- Test is carried out on granular size having diameter > 4.75mm and of more than 5% of the sample quantity

- Diamon /flattened quantity of the sample is taken equally to weighted average of the results obtained for each granular size

1 Granular component Specified in table 1 (Dmax 25mm)

Material passing sieve 0.075 mm Maximum 2/3 of granular passing sieve 0.425mm

8 Percent by weight of aggregate with diamond or flattened shapes, %

Granular passing sieve 2mm, minium 50%

The portion of the material passing the 0.075 mm sieve shall not be greaterGENERAL SPECIFICATIONS 05100 6 of 54

Unacceptable Materials

All materials that fail to meet the specifications will be promptly rejected and must be removed from the work site at the Contractor's expense, without any time extensions for delays caused by this issue If defects in unacceptable materials can be corrected, they may not be used until they pass testing and receive approval from the Engineer.

Aggregate Subbase Material Requirements

The aggregate for subbase must consist of hard, durable particles from crushed stone, slag, or gravel, combined with natural or crushed sand or other fine mineral matter This composite material should be free from organic matter and clay lumps, ensuring it can be easily compacted to create a stable subbase Additionally, the Aggregate Subbase Material must meet the specifications outlined in Tables 1, 2, and 3.

Aggregate with Dmax = 37.5mm is appropriate with Subbase;

Aggregate with Dmax = 25mm is appropriate with Base;

Aggregate with Dmax = 19mm is appropriate with leveling and strengthening existing pavement structure in rehabilitation of road.

Table 1 Granular Composition of Aggregate

Dmax 37.5mm Dmax 25mm Dmax 19mm

Percent by weight of aggregate with diamond or flattened shapes,

22TCN333-06(method II-D)(AASHTO T191)GENERAL SPECIFICATIONS 05100 5 of 54

When utilizing crushed gravel, it is essential that at least 50% of the particles retained on the No 4 sieve possess a minimum of one fractured face by weight Additionally, the liquid limit and plastic limit should be assessed through testing the fraction that passes through the 0.425 mm sieve.

- Diamon /flattened quantity of the sample is taken equally to weighted average of the results obtained for each granular size

1 Granular component Specified in table 1 (Dmax 25mm)

Material passing sieve 0.075 mm Maximum 2/3 of granular passing sieve 0.425mm

8 Percent by weight of aggregate with diamond or flattened shapes, %

Granular passing sieve 2mm, minium 50%

The portion of the material passing the 0.075 mm sieve shall not be greaterGENERAL SPECIFICATIONS 05100 6 of 54 than 0.66 (two thirds) of the fraction passing the 0.425 sieve.

To meet grading requirements and ensure satisfactory bonding, any necessary filler must be uniformly blended with the crushed base course material, as approved by the Engineer The filler must come from approved sources, be free of hard lumps, and contain no more than 25 percent of material retained on the 4.75 sieve, in accordance with AASHTO T112 standards.

(*) Liquid limit, plastic limit are determined by testing the portion passing sieve 0.425,mm.

- Diamond /flattened quantity of the sample is taken equally to weighted average of the results obtained for each granular size.

CONSTRUCTION REQUIREMENTS

Particular Provision on the Commencement of the Works

Construction of the Subbase and Base courses, along with pavement works, must not begin until the Contractor has properly completed and the Engineer has accepted the slope formation and slope protection in both cutting and embankment sections Additionally, prior to spreading the base or subbase, the Engineer may require a thorough inspection and curing of the subgrade surface.

Subbase and base courses must be evenly distributed using a spreader, followed by compaction to achieve the specified design thickness, grade, gradient, cross-fall, and camber as outlined in the drawings Tolerances are detailed in Table 4 below.

TABLE 4 Required geometric dimension and flatness of subbase and base

Thickness + 20 mm + 15 mm At all cross- sections

Width Not less than design

Not less than designGENERAL SPECIFICATIONS 05100 7 of 54

Flatness: biggest gap under 3-m straightness

(a) Surface of all subbases and bases shall be uniform, containing sufficient moisture Camber of all faces shall be as specified in the Drawings.

(b) Upon testing the uniformity of the bituminous treated base course, incoherent materials shall be removed by using stiff broom

3.3 Trial Sections a) Before either subbase or base construction is started, the Contractor shall spread and compact trial sections as directed by the Engineer. The purpose of the trial section is to check the suitability of the materials and the efficiency of the equipment and construction method proposed to be used by the Contractor Therefore, the Contractor must use the same materials, equipment and procedures which he proposes to use for the main work One trial section about

For every type of material and construction equipment or procedure proposed, a designated area of 500 m² must be allocated Density tests and additional assessments as specified by the Engineer are required Should the Engineer determine that the materials are unsuitable for the subbase or base based on trial observations, the Contractor will be responsible for their removal and the construction of a new trial section, without any extension of time due to this delay Furthermore, if there are changes in the basic conditions regarding the type of material or procedure during the work execution, new trial sections must be constructed.

3.4 Rectification of Unsatisfactotry Aggergate Base or Subbase a) Areas with a thickness or surface uniformity not satisfying the tolerances herein specified, or which develop irregularities in the surface during or after construction, shall be rectified by loosening the surface and removing or adding material as required, followed by reshaping and re-compacting. b) The Aggregate Subbase or Aggregate Base which is too dry for compaction, in terms of moisture content specified in theSpecification or as directed by the Engineer, shall be corrected by scarifying the material followed by sprinkling with an adequateGENERAL SPECIFICATIONS 05100 8 of 54 quantity of water and thoroughly mixing by means of equipment approved by the Engineer, and re-compacting. c) The Aggregate Subbase or Aggregate Base which is too wet for compaction, as defined by the moisture content specified in the Specification or as directed by the Engineer, shall be rectified by scarifying the material followed by intermittent working by motor grader or other approved equipment to air-dry the material under dry weather conditions Alternatively, or if sufficient drying cannot be achieved by re-working the loose material, the Engineer may direct that the material be removed from the work and replaced with a suitably dry material. d) The Aggregate Subbase or Aggregate Base which becomes saturated by rain or flooding or otherwise after it has already been satisfactorily compacted according to this Specification Section will generally require no rectification work provided its material properties and surface uniformity meet the requirements of this Specification Section. e) Rectification of the Aggregate Subbase or Aggregate Base which does not meet the density or material property requirements of this Specification Section, shall be as directed by the Engineer and may include additional compaction, loosening followed by moisture content adjustment and re-compacting, removal and replacement of the material, or the application of an additional thickness of material.

3.5 Equipment Used for Aggegate Subbase and Base a) Equipment and method used shall place the Aggregate Subbase and

Aggregate Base to the lines, levels, grades, dimensions and cross- section shown in the Drawings and as directed by the Engineer.

Aggregate spreading must be conducted using a self-propelled aggregate spreader with at least four wheels and pneumatic tyres on two axles, unless otherwise directed by the Engineer The spreader should have positive controls to ensure even distribution of material across the full width of the bituminous layer Alternative types of spreaders may be utilized if they achieve similar results and receive Engineer approval The Engineer reserves the authority to halt the use of any equipment deemed inferior in quality, mandate its removal, and require replacement with suitable equipment or modifications to the operation method at any time.

The Contractor must promptly adhere to instructions from the Engineer without any claims for compensation or time extensions Prior approval from the Engineer is required before utilizing any equipment or plant Additionally, the Contractor is responsible for employing qualified and trained personnel to execute the Works, while the Engineer reserves the authority to remove and replace any operators, mechanics, or laborers as deemed necessary.

3.6 Placing, Spreading and Compacting Aggegate Subbase and Base

Placement, spreading, and compaction of Aggregate Subbase and Aggregate Base must be avoided during rainfall, and compaction should not occur if the material's moisture content is outside the specified range.

The aggregate subbase and base materials must be placed uniformly according to drawing specifications, ensuring the required compacted thickness is achieved Prior to placement, the subgrade must be prepared as outlined in Specification Section 03400 “Embankment Construction.” If multiple layers are necessary, each must be compacted according to Sub-Section 3.6 before the next layer is added Material placement should commence at a point designated by the Engineer, and the area for laying the subbase and base must be prepared and approved by the Engineer at least 200 meters in advance Hauling equipment is permitted over completed sections, provided it does not cause damage and traverses the full width to prevent rutting; the Engineer may halt hauling if it is deemed damaging.

For subbase thicknesses of 180mm or less and base thicknesses of 150mm or less, materials can be spread and compacted in a single layer For thicker requirements, the aggregate must be laid in two or more layers of equal thickness, adhering to specified limits unless directed otherwise by the Engineer The aggregate should be delivered as a uniform mix with proper moisture content, ensuring even distribution Approved methods must be used for spreading and shaping to avoid segregation of materials, with any segregated portions corrected or replaced After final spreading, layers must be compacted using approved equipment, starting from the edges and moving inward, with adjustments made for any irregularities Areas inaccessible to rollers require thorough compaction with tampers At shift's end, the surface must be shaped to prevent water pooling For surfaces receiving a prime coat, additional compaction is needed to create a tightly locked, stable surface without open pores, achieved solely through compaction without adding fine aggregates The Engineer may specify pneumatic rollers for final compaction to prevent damage to the aggregate base.

Compaction must occur when the moisture content of the material is between 3% below and 2% above the optimum moisture content If the underlying material is soft, compaction should cease until the Engineer directs necessary rectifications During the spreading, compacting, and leveling of subbase and base course materials, it is crucial to avoid disturbing already compacted layers and the finished surfaces, especially in areas where equipment turns Any damage caused by mixing layers must be rectified by the Contractor at their own expense to the Engineer's satisfaction If the subbase or base material does not meet the required finish, the Contractor is responsible for making the necessary corrections at their expense.

Granular material must be compacted to achieve a density of at least 100 percent of the maximum density, as specified by 22TCN 333-06 (method II-D) and AASHTO T180 (method D) Field density will be assessed following AASHTO T191, with the Engineer conducting random measurements of test holes throughout the project to ensure adherence to specifications and to identify any un-compacted layers necessary for achieving the required nominal depth of material.

Cutting the test holes and refilling with materials properly compacted shall be done by the Contractor under the supervision of the Engineer, at the Contractor's expense.

3.7 Control of Traffic on Subbase and Base Surface a) Construction traffic or other traffic shall not be permitted to travel on any aggregate layers, prior to the construction of the final surfacing, except where directed or permitted by the Engineer. b) The aggregate base shall not be opened to traffic until shaping and compaction are substantially completed.

GENERAL SPECIFICATIONS 05100 12 of 54 c) Pending the construction of the final surfacing, the Aggregate Base shall be maintained as follows:

To ensure optimal maintenance of the aggregate base, it is essential to regularly drag broom the surface Traffic management will involve implementing temporary speed limits, and during working hours, vehicles will be directed through clearly marked traffic lanes These lanes will be frequently adjusted to promote an even distribution of traffic across the entire surface.

In areas where the pavement is excessively dry, leading to insufficient surface stability that won't improve with traffic or rolling, and when rain is not expected or has been inadequate, it is essential to uniformly apply water across the entire surface This application should be done gradually, using up to 4 liters per square meter, to prevent flooding or erosion of the surface.

Trial Sections

Before commencing subbase or base construction, the Contractor must spread and compact trial sections as directed by the Engineer These trial sections are essential for assessing the suitability of materials and the effectiveness of the proposed equipment and construction methods It is crucial that the Contractor utilizes the same materials, equipment, and procedures intended for the main work during these trials.

For every type of material and construction equipment or procedure proposed, a 500 m² area must be designated for testing Density tests and additional evaluations will be conducted as instructed by the Engineer Should the Engineer determine that the materials are unsuitable for the subbase or base based on trial observations, the Contractor must remove the materials at their own expense and construct a new trial section without any time extension for the resulting delay Furthermore, if there are changes in the basic conditions regarding materials or procedures during the project's execution, new trial sections will need to be created.

3.4 Rectification of Unsatisfactotry Aggergate Base or Subbase a) Areas with a thickness or surface uniformity not satisfying the tolerances herein specified, or which develop irregularities in the surface during or after construction, shall be rectified by loosening the surface and removing or adding material as required, followed by reshaping and re-compacting. b) The Aggregate Subbase or Aggregate Base which is too dry for compaction, in terms of moisture content specified in theSpecification or as directed by the Engineer, shall be corrected by scarifying the material followed by sprinkling with an adequateGENERAL SPECIFICATIONS 05100 8 of 54 quantity of water and thoroughly mixing by means of equipment approved by the Engineer, and re-compacting. c) The Aggregate Subbase or Aggregate Base which is too wet for compaction, as defined by the moisture content specified in the Specification or as directed by the Engineer, shall be rectified by scarifying the material followed by intermittent working by motor grader or other approved equipment to air-dry the material under dry weather conditions Alternatively, or if sufficient drying cannot be achieved by re-working the loose material, the Engineer may direct that the material be removed from the work and replaced with a suitably dry material. d) The Aggregate Subbase or Aggregate Base which becomes saturated by rain or flooding or otherwise after it has already been satisfactorily compacted according to this Specification Section will generally require no rectification work provided its material properties and surface uniformity meet the requirements of this Specification Section. e) Rectification of the Aggregate Subbase or Aggregate Base which does not meet the density or material property requirements of this Specification Section, shall be as directed by the Engineer and may include additional compaction, loosening followed by moisture content adjustment and re-compacting, removal and replacement of the material, or the application of an additional thickness of material.

3.5 Equipment Used for Aggegate Subbase and Base a) Equipment and method used shall place the Aggregate Subbase and

Aggregate Base to the lines, levels, grades, dimensions and cross- section shown in the Drawings and as directed by the Engineer.

The spreading of materials must be carried out using an approved self-propelled aggregate spreader with a minimum of four wheels and pneumatic tyres on two axles, unless directed otherwise by the Engineer This equipment should feature positive controls to ensure uniform material distribution across the full width of the bituminous surface Alternative aggregate spreaders may be permitted if they achieve similar results and receive the Engineer's approval Additionally, the Engineer reserves the right to halt the use of any equipment deemed substandard and may require its replacement or modification of operational methods at any time.

The Contractor must promptly adhere to instructions from the Engineer without any claims for compensation or time extensions Prior approval from the Engineer is required before using any equipment or plant Additionally, the Contractor is responsible for employing skilled and trained personnel to execute the Works, following sound technical practices The Engineer reserves the authority to remove any operators, mechanics, or laborers and to mandate their replacement whenever deemed necessary.

3.6 Placing, Spreading and Compacting Aggegate Subbase and Base

The placement, spreading, and compaction of Aggregate Subbase and Aggregate Base must be avoided during rainfall, and compaction should only occur when the material's moisture content is within the specified range.

The aggregate subbase and base material must be placed uniformly according to drawing specifications to achieve the required compacted thickness Prior to placement, the subgrade should be prepared in line with Specification Section 03400 “Embankment Construction.” If multiple layers are necessary, each must be compacted as outlined in Sub-Section 3.6 before adding the next layer Material placement will start at a point designated by the Engineer, and the area for laying subbase and base materials must be completed and approved by the Engineer at least 200 meters in advance Hauling equipment may traverse completed sections of the subbase and base courses, provided it does not cause damage and covers the full width to prevent rutting The Engineer reserves the right to halt any hauling if it is deemed to cause damage to completed or partially completed sections.

For thickness requirements of 180mm for subbase and 150mm for base or less, materials can be compacted in one layer; for greater thicknesses, they must be spread in multiple layers with a maximum compacted thickness as specified, unless directed otherwise by the Engineer The Aggregate Subbase and Base must be uniformly mixed and spread at the specified moisture content to prevent segregation Approved methods should be used for spreading and shaping to avoid separating fine and coarse aggregates, with any segregated material corrected or replaced After spreading, each layer must be compacted fully using approved equipment, starting from the edges and moving inward, ensuring the surface is smooth and uniform by addressing any irregularities Thorough compaction is required in areas inaccessible to rollers, with surfaces shaped to prevent water ponding For surfaces receiving a prime coat, further compaction is necessary to achieve a stable, tightly locked surface without open pores, and no soil or fine aggregates should be added; compaction should be achieved solely through mechanical means, avoiding vibration during final compaction, though pneumatic rollers may be used if static rollers risk damaging the aggregate base.

Compaction must occur when the moisture content of the material is within 3% below to 2% above the optimum moisture content If the underlying material is soft, compaction of the subbase and base course must cease, and the Engineer will direct necessary rectifications During the spreading, compacting, and leveling processes, care must be taken to avoid damaging previously compacted layers or the finished surfaces, especially where equipment turns Any damage that mixes different layers must be rectified by the Contractor at their own expense, ensuring satisfaction of the Engineer If the subbase or base material does not meet the required finish, the Contractor is responsible for making the necessary corrections at their cost.

Granular material must be compacted to achieve a density of at least 100 percent of the maximum density, as specified by 22TCN 333-06 (method II-D) and AASHTO T180 (method D) Field density tests will be conducted in accordance with AASHTO T191 The Engineer will randomly measure test holes during the project to ensure compliance with specifications and assess the depth of any un-compacted layers necessary to reach the required nominal depth of material.

Cutting the test holes and refilling with materials properly compacted shall be done by the Contractor under the supervision of the Engineer, at the Contractor's expense.

3.7 Control of Traffic on Subbase and Base Surface a) Construction traffic or other traffic shall not be permitted to travel on any aggregate layers, prior to the construction of the final surfacing, except where directed or permitted by the Engineer. b) The aggregate base shall not be opened to traffic until shaping and compaction are substantially completed.

To ensure optimal maintenance of the aggregate base, it is essential to perform regular drag brooming Traffic management will be implemented through temporary speed limits, and during operational hours, vehicles will be directed through clearly marked traffic lanes Additionally, frequent transverse shifts of these lanes will be employed to promote an even distribution of traffic across the entire surface.

In situations where the pavement is excessively dry, hindering surface stability from improving due to traffic or rolling, and when rain is either not expected or has been inadequate, a uniform water application is essential It is recommended to apply up to 4 liters per square meter in gradual increments to prevent flooding or scouring of the surface.

3.8 Testing a) The amount of supporting test data required for initial approval of the Quality of the material shall be as directed by the Engineer, and shall include all the tests specified in this Section on at least three representative samples from the proposed material source, selected to represent the range of material Quality likely to be obtained from the source Test sample shall be taken as representative for the product lot or the test/check section Subject to test purpose and specific conditions, sample shall be taken in different methods and in compliance with the following basis requirements:

 Upon taking sample at the outlet, sample of the entire materials at the outlet shall be taken without littering

When sampling materials from a band conveyor, it is essential to collect samples from all cross-sections, with particular emphasis on obtaining samples of fine-grain materials.

 Sample shall not be taken at outlet or on the band conveyor at the very beginning time of production shift because it is not stable yet.

Control of Traffic on Subbase and Base Surface

Construction traffic is prohibited on aggregate layers before the final surfacing is completed, unless authorized by the Engineer Additionally, the aggregate base must not be opened to traffic until significant shaping and compaction work has been finished.

To ensure optimal maintenance of the aggregate base, it is essential to perform drag brooming consistently Traffic management will involve implementing temporary speed limits and designating specific traffic lanes during working hours Additionally, frequent transverse shifts of these lanes will facilitate an even distribution of traffic across the entire surface.

In situations where the pavement is excessively dry, hindering surface stability and where rain is not expected or has been inadequate, it is essential to uniformly apply water across the entire surface This should involve a gradual application of up to 4 liters per square meter to prevent flooding or damage to the pavement.

Testing

The Engineer will determine the amount of supporting test data needed for the initial approval of material quality, which must include all specified tests conducted on at least three representative samples from the proposed material source These samples should accurately represent the expected range of material quality Samples must be collected to reflect the product lot or specific test section, and the collection methods should comply with the established requirements based on the testing purpose and conditions.

 Upon taking sample at the outlet, sample of the entire materials at the outlet shall be taken without littering

When sampling materials at the band conveyor, it is crucial to collect samples from all cross-sections, with particular emphasis on obtaining samples of fine-grain materials.

 Sample shall not be taken at outlet or on the band conveyor at the very beginning time of production shift because it is not stable yet.

To collect a sample from a heap, it is essential to first remove and level the top layer, creating a flat area measuring at least 50cm x 50cm This process should include digging a square hole to ensure an adequate quantity of sample is obtained from each heap.

 Upon taking sample on the already-spread subbase / base course, hole must be excavated in vertical direction and sample shall be taken throughout the structure’s thickness.

After the approval of a proposed material's quality, all related quality tests must be repeated at the Engineer's discretion if any changes occur in the material, its source, or its production method Additionally, a routine quality control testing program is essential to manage the variability of materials delivered to the site, with the specific extent of testing determined by the Engineer to ensure compliance with established requirements.

The Contractor must conduct tests on a sample group of three for each material source proposed for approval, ensuring compliance with the properties outlined in Tables 1, 2, and 3 of Clause 2.5 Additionally, materials must meet the specifications listed in Table 5.4 To validate that the proposed materials fulfill the Project’s requirements, a manufacturer's certificate and test report must be provided.

Inspection of aggregate materials delivered to the construction site is essential for ensuring quality Samples must be collected from the storage area according to the frequency outlined in Table 5.6 It is crucial that these materials meet all specified properties listed in Tables 1 and 2.

Table 5 Tests and Test Frequency for Subbase Course

4 PP Index = Plasticity Index Ip x % material passing sieve 0.075mm

5 Percent by weight of aggregate with diamond or flattened shapes, % < 15 1 sample/300m3

7 Los-Angeles wear of aggregate (LA), % < 50 1 sample/3000m3

8 Soaked CBR at K100 density, in 96 hours, % ≥ 35 1 sample/3000m3

9 Abrasivity by Sodium or Magnesium < 10 1

Table 6 Tests and Test Frequency for Base Course

Material passing sieve 0.075mm Maximum 2/3 granular proportion passing sieve 0.425mm

3 Percentage of fractured face Granular passing sieve 2mm, minimum 50%

6 PP Index = Plasticity Index Ip x % material passing sieve 0.075mm < 45 1 sample/250m3

7 Percent by weight of aggregate with diamond or flattened shapes, % < 10 1 sample/250m3

9 Los-Angeles wear of aggregate (LA), % < 35 1 sample/3000m3

10 Soaked CBR at K100 density, in 96 hours, % ≥ 100 1 sample/3000m3 d) Examination during construction period: During construction period, the contractor shall regularly conduct tests and check the following contents:

 Moisture, aggregate material separation (observed by eyes and checking sieve particle)

The compacted density of each finished aggregate foundation layer must be tested to ensure compliance This testing process requires certification of the sub-base and base aggregates using the sand cone method, following standards outlined in 22TCN346-06 or AASHTO T191 Tests should be conducted at a frequency of one test per 500 square meters.

The flatness and geometric factors must be evaluated in accordance with the criteria outlined in Item 3.2 of Table No 5.4, as this data will serve as the foundation for the acceptance of the work Additionally, any holes created during density testing or other procedures must be backfilled with the specified material by the Contractor.

GENERAL SPECIFICATIONS 05100 15 of 54 delay and compacted to the density and surface tolerance requirements of these Specification section.

MEASUREMENT AND PAYMENT

Method of Measurement

The measurement of Aggregate Subbase and Aggregate Base will be calculated in cubic meters of compacted material, based on uniform cross sections in the Drawings or approved by the Engineer for non-uniform thickness, with horizontal lengths measured along the road centerline Materials outside the specified design limits will not be accounted for, and trial sections will be included in the overall quantity Preparation and maintenance of the subgrade will not be eligible for payment, nor will there be separate measurements for Running Course gravel used for temporary surface protection Additionally, no extra payments will be made for repairs due to traffic or natural conditions, deficiencies in the subbase or base course, or adjustments to moisture content directed by the Engineer prior to compaction.

Basis of Payment

Payments will be made at the contract price per unit for the quantities specified in the Bill of Quantities This payment will fully compensate for all work outlined in this section, including hauling, supplying, placing, compacting, finishing, and testing materials It also covers the supply and placement of the running course, maintenance of the surface under traffic, and all labor, materials, tools, equipment, and incidental costs necessary to complete the work.

CEMENT/ LIME TREATED BASE COURSE (Stabilization)

General Description

This project involves the supply, processing, hauling, spreading, watering, compacting, and finishing of cement lime or a stabilized base course on a prepared surface, following the specifications outlined in the drawings or as directed by the Engineer The processing includes layer preparation, spreading, blending, and any other necessary operations to ensure compliance with the requirements of Vietnamese Industrial Standard 22 TCN 245-98.

At the soft soil treated locations, the use of cement treated base course shall be minimized

Aggregate cement treated base course material shall conform with specifications and testing frequency as stipulated in Table 7 below:

Requirements on Properties and Testing Frequency of Aggregate Materials used for Cement Treated Base Course

No Properties (Test Method) Criteria Testing frequency

1 Granular component Specified in table 5.2

8 Soak CBR K100, 96 hours, ≥ 90 Sample/3000m3GENERAL SPECIFICATIONS 05100 17 of 54

Cement/Lime stabilized pavement courses shall be constructed using a plant-mixed material, which comprises a mixture of unbound pavement material and hydraulic stabilizing agent.

Requirements on Granular Components of Cement Treated Aggregate

Size of square sieve mesh

Percentage passing sieve (Dmax = 25 mm)

Materials

The stabilizing agent must consist of cement, lime, or a combination of both The cement utilized should be Ordinary Portland Cement Type 1, conforming to ASTM C150 and the Vietnamese Standard TCVN 2682-92 The lime can either be Hydrated Lime (Ca(OH)2) or Quick Lime (CaO).

Unless otherwise directed by the Engineer, the unbound material shall be (basecourse) with a CBR not less than 80%

Water used for stabilization must be clean and devoid of harmful substances such as oil, salt, sugar, alkali, and organic matter, as these can negatively affect the hardening process of stabilized pavement.

Unless otherwise stipulated by the Engineer a surface applied curing agent other than the temporary use of water, may be either rapid setting bitumen emulsion or cut back bitumen.

The Contractor shall nominate the source of supply of cement and lime at least 28 days before commencing stabilization works.

The Contractor shall provide a sample of proposed cement and lime for testing Samples shall be a minimum of 10 Kg in air-tight container.

The Engineer will make a decision on the acceptance or rejection of the sample within 14 days of receipt Proper storage and handling of cement and lime must adhere to the guidelines outlined in item 3.1.2 – Portland Cement, as specified in Section 06100 – Concrete and Concrete Structures.

Material Composition

Before accumulating materials, the Contractor must provide a proposed mix formula to the Engineer, which will be utilized to ascertain the percentage ratio of cement and lime in the pavement material This submitted formula should yield a clear and definitive single value.

 The percentage of aggregate passing each specified sieve.

 The percentage of stabilizing agent to be added.

 The proposed moisture content of the complete mix.

The Engineer will determine the desired formula and so advise the Contractor in writing.

The procedure to determine the optimum cement/lime content shall be:

Trial batches of the approved pavement material will be created with cement/lime content levels of 3%, 5%, and 7% by weight, with each batch weighing around 100 kg Three specimens from each batch will undergo compression testing, and the mean compression strength will be evaluated after a 7-day moist curing period.

To ensure optimal pavement performance, it is crucial to use only the minimum required amounts of cement and lime to meet specified strength standards Overuse of cement can lead to issues such as embrittlement, shrinkage, and cracking, which negatively impact the overall durability of the pavement.

Required Strength of Cement Treated Base Course

Limit of Compress Strength Requirement

Compressive (after 28 days) Flexural Strength

Flexural Strength (after 28 days) shall be tested and determined byVietnamese Standard 22 TCN 73-84 or other method approved by theEngineer.

Preliminary Trial Section

The Contractor must conduct a trial section of at least 100 meters before commencing mass construction, under the supervision of the Engineer This trial will help finalize the technology sequence and line, while also assessing the actual quality of the cement aggregate and the capabilities of the mixing plant, hauling equipment, and construction machinery.

Equipment

The mixing of stabilized pavement materials can be efficiently conducted using various methods, including power-driven pugmills, rotary drum mixers, batch plants, or continuous mixing plants Additionally, with the Engineer's approval, alternative methods such as mechanical spreaders and specially designed single rotor plants may be utilized for in-situ mixing of stabilized road materials.

When operating a pugmill, rotary drum, or batch plant, it is essential to proportion dry materials by mass The Engineer must approve and calibrate all scales and weighing devices Additionally, scales designated for weighing cement and lime should be exclusively used for that purpose to ensure accuracy and compliance.

Mixing by continuous type mixing plant shall be carefully and continuously monitored.

The dry material shall be proportioned by volume The continuous feeder shall be such that it allows the feed rate of different aggregate sizes to be adjusted separately.

The mixer must include metering devices to accurately control material proportions Additionally, the mixing plant's capacity and location should align with the construction line to ensure that mixing, hauling, spreading, and compacting are completed within 120 minutes, prior to the cement setting time.

Meters and feeders shall be interlocked and synchronized to maintain the specified proportions of cement/lime and water.

Delivery

Trucks used for delivering stabilized material must be equipped with tightly secured full cover tarpaulins to prevent moisture loss To ensure quality, measures should be implemented to minimize material segregation during both loading and unloading processes Additionally, the material should be discharged directly into the hoppers of paving machines to avoid any spillage.

Laying

Stabilized material shall be deposited and spread on approved prepared surface in one (1) operation using a self propelled mechanical tamper spreader incorporating the following features:

 Means of pushing each truck during spreading and having a rapid acting device to engage and release the truck.

 A receiving hopper into which trucks can discharge the paving material.

 Distributing screws to place the material evenly in front of the screed plate without segregation.

 Automatic tamping device or vibrating screed.

 An adjustable screed capable of providing a smooth even surface for width up to 3.5 metres with easy adjustment to permit variation in the width of spread.

 Effective steerage such that the material can be laid to a true line.

Automatic screed controls enhance the self-leveling action of finishes by incorporating attachments for automatic level control These controls can be operated using a joint matching shoe, fixed line, traveling straight edge, leveling beam, or other approved devices, ensuring precise leveling for optimal results.

The Screed shall be adjustable to the required cross fall and procedure a finish surface texture of uniform appearance.

In-Situ Construction

To ensure effective stabilization of the pavement, it should be lightly compacted to expose any irregularities in the material spread This process allows stabilizing equipment to move across the area without displacing the surface.

The layer be surface shall be shaped and trimmed to level, cross section and final level and compacted depth.

The cement/lime shall be uniformly spread on the layer surface at the specified rate as instructed by the Engineer using a suitable mechanical spreader designated for the purpose.

Stabilizing operations using this method will not be allowed during windy periods, which will cause loss of cement/lime or cause a nuisance or danger to people or property.

Mixing

The "in-situ" method for mixing stabilized materials requires a specially designed single rotor plant, specifically constructed for the effective mixing of road-making materials This approach ensures optimal performance and quality in the stabilization process.

 Mixing the cement/lime with the nominated material uniformly to the full depth to be stabilized.

 Adding water to the materials while being agitated by the mixer.

 Controlling the added water so that the percentage of water may be adjusted between 1% and 10% by weight of the material being mixed.

The layer to be stabilized shall be ripped or typed to the specified depth to be treated prior to spreading the cement.

The mixer must be adjusted to ensure a uniform mix throughout the entire area, achieving the specified depth and cement content while maintaining the required moisture level for an optimal compacted mixture.

Compaction

After placing the layer, it must be compacted according to the approved procedure established during preliminary trials The construction of the cement-treated base course is permitted to be completed in a single operation, involving one spreading and one compacting, to ensure optimal contact and maintain the bearing capacity of the structural layers To achieve the required compaction quality, the thickness of the cement-treated base course should be 25 cm after compaction, and the Contractor must utilize adequate equipment to meet this requirement The Contractor's capacity will be assessed by evaluating the compaction quality of the trial section as outlined in Clause 5.4 of the General Specifications.

The on-site density of the cement-treated base course is evaluated using the AASHTO T191 method, with testing conducted every 500 m² The density must be at least 100 percent of the laboratory-compacted density, which is determined according to TCN 333-06 (Method II-D) or AASHTO T180, Method D.

Finishing

The finishing of the cement-treated base course must occur during compaction, focusing on flattening any convex areas without addressing concave sections Any excess material removed should not be reused.

The entire process from putting water into mixer until completion of compacting and finishing work shall not over starting time of cement setting

(120 minutes for Portland cement if no admixture is used to delay the setting), including time waiting for compacting.

During the finishing process, the Contractor is responsible for filling all test and core holes with the specified material and ensuring proper compaction to achieve the required density and surface tolerance outlined in this Specification.

Joint

Small vibrating roller shall be used to carry out additional compaction at the surrounding area of the steel form at both sides of spreading track and transverse joint.

At the end of each working shift, a steel form must be positioned perpendicularly at the termination of the spreading track to establish a transverse joint, known as a working stop slit Before proceeding with the next track or area following the working stop slit, it is essential to remove the steel form and thoroughly water both the longitudinal and transverse joints.

Transverse joints shall be formed immediately before commencement of the day’s operation and following any delay in excess of two (2) hours in the continuity of the stabilizing operator.

Curing

4 hours after compacting (2 hours in case of scorching sunny), the cement treated base course shall be covered for curing by either one of the following two methods:

 Curing of finished surface shall be applying a rapid setting bitumen emulsion or cut back bitumen at the application rate of 0.8-1.0 litre/m2 or as approved by the Engineer

 The surface shall be covered with 5cm sand and kept wet continuously in

The upper structure shall not be constructed before 7 curing days (before starting, covering sand shall be removed).

Traffic Restrictions

Unless otherwise provided, public traffic will not be permitted on the cement treated aggregate course until either the surface course or a wearing surface has been placed.

To ensure traffic safety and accommodate on-site travel, the Engineer must thoroughly assess the 7-day strength of the cement-treated base course This evaluation is crucial for establishing the weight limit for vehicles permitted to operate on the surface, with a maximum speed restriction of 30 km/h.

Any damage to the cement treated aggregate course shall be repaired by the Contractor at no cost to the Employer.

Inspection and Acceptance

Allowable tolerance of the cement treated base course is specified in detail in the table below:

Required geometric dimension and flatness of cement treated base cour se

Thickness ± 5% At all cross- sections

Width Not less than design

Flatness: big gap under 3-m straightness ≤ 5mm Every 100m

Samples will be collected from two groups (totaling six samples) every 500m² or daily for the cement-treated base course These samples will be tested for strength according to the specifications outlined in Table 9 of Clause 5.3 – Material Composition.

To ensure the quality of the completed cement treated base course at the site, core samples will be taken every 500m² This process will assess the strength of the material while also verifying its thickness and dry density.

Method of Measurement

Payment will be based on the cubic metres of cement or lime stabilized material laid as per the Drawings or Engineer's instructions, ensuring it is compacted, tested, and accepted The payment quantity will reflect the nominal dimensions and shape indicated in the plans, measured along the survey's centreline Throughout the work, precise control of each course's thickness is essential to achieve the required thickness post-compaction Additionally, water used for mixing or other purposes will not be billed separately, and curing seal for hardening concrete is included in the unit cost of the cement-treated base course.

Basis of Payment

Payment for the work will be made at the Contract unit price per cubic metre for stabilized base course This payment fully compensates for all materials, hauling, placing, mixing, compacting, sprinkling, proof rolling, finishing, shaping, curing, and all labor, equipment, tools, and other necessary incidentals to complete the specified work.

Pay Item No Name Unit of Measurement

05100-3 Cement Stabilized Base Course cubic metre

1.2 Reference Standards 25 1.3 Equipment 27 1.3.1 Distributor 27 1.3.2 Bitumen Heater 27 1.3.3 Bitumen Mixing Plant 27 1.3.4 Hauling Equipment 31 1.3.5 Bituminous Pavers 31 1.3.6 Rollers 32 1.3.7 Aggregate Spreader 32 1.3.8 Power Broom and Blower 32 1.4 General Requirement 32 1.4.1 Weather 32

1.4.2 Protection of Existing Work 32 1.4.3 Layers of Bituminous Courses 33 1.4.4 Overlay 33 1.4.5 Finished Work Samples 33

2.1 Description 33 2.2 Construction 34 2.3 Method of Measurement 34 2.4 Basis of Payment 34

3.1 Description 34 3.2 Material 34 3.3 Construction 35 3.4 Method of Measurement 35 3.5 Basis of Payment 35

5.1 Description 37 5.2 Material 37 5.3 Construction 37 5.4 Method of Measurement 38

5.5 Basis of Payment 38 GENERAL SPECIFICATIONS 05200 - 25 of 54

6 BITUMINOUS PLANT-MIX MATERIAL-ASPHALT CONCRETE

7 BITUMINOUS SURFACE TREATMENT (BST) PAVEMENT 48

7.1 General 48 7.2 Material 49 7.3 Composition 49 7.4 Construction 50 7.5 Method of Measurement 50 7.6 Basis of Payment 50

This section outlines the processes involved in treating and repairing existing bituminous pavements, as well as the supply and installation of new materials to complete the pavements as specified in the Drawings and directed by the Engineer.

The Engineer will determine the scope and treatment of existing pavement to be integrated into the new project based on cross-sections prepared by the Contractor The Contractor must collaborate in this study, preparing any necessary additional cross-sections or levels to enhance the earthworks calculations and provide skilled personnel to support the Engineer's efforts.

The following Standards in their latest edition shall be particularly applied to the works covered by this Specification Section:

1 22TCN249-98 Specification for construction technology and acceptance of bituminous pavement – technical specifications.

2 22TCN345-06 Specifications for construction technology and acceptance of thin bituminous cover with high roughness.

4 22TCN279-01 Technical requirement and testing method of solid asphalt.

5 22TCN354-06 Standard of acid emulsified asphalt – Technical requirement and testing method.

6 22TCN250-98 Technical specifications for construction and approval of acid emulsified asphalt macadam pavement.

7 22TCN271-01 Technical specifications for construction and approval of bituminous pavement

8 22TCN277-01 Specifications for inspecting and assessing flatness of pavement based on international roughness index IRI

9 22TCN278-01 Specifications for determining pavement roughness by sand pour method

10 22TCN318-04 specifications for determining abrasion of aggregate by Los-Angeles method

11 AASHTO M17 Stone powder used for bitum mixture (surface covering)

12 AASHTO M20 Determining penetration of asphalt seal

13 AASHTO M226 Viscosity Graded Asphalt Cement

14 AASHTO PP37 Determining IRI for pavement roughness quantity

15 AASHTO T11-05 Material Finer Than 75-μm (No.200) sie in Mineralm (No.200) sie in Mineral

16 AASHTO T27-99 Sieve analysis of coarse and fine aggregate ASTM

17 AASHTO T49 Determining needle penetration of bitumen material

19 AASHTO T51 Softness of Bitumen material

20 AASHTO T53-96 (2004) Softening point of Bitumen (Ring-and-Ball)

21 AASHTO T96 Determining abration strength of fine-grain mixture by Los-angles

22 AASHTO T104 Determining sodium sulfate or magnesium sulfate in aggregate mixture

23 AASHTO T164 Determining distillation quality from Bitumen used for bituminous pavement

24 AASHTO T165 Water impact on cohesiveness of compacted bituminous mixture

25 AASHTO T166 Determining specific gravity of compacted bituminous mixture

26 AASHTO T168 Taking sample of surface covering bitumen

27 AASHTO T170 Retrieving asphalt from solution by Abson method

28 AASHTO T176 Determining bituminous quantity in aggregate mixture by the equivalent sand test

29 AASHTO T179 Heat and air impacts on asphalt material (thin membrane test)

30 AASHTO T182 Covering and opening up stone-bitumen mixture

31 AASHTO T209 Determining the maximum specific gravity in bitumen surface covering mixture

32 AASHTO T230 Method B Standard Method of Test for

Determining Degree of Pavement Compaction of Bituminous Aggregate Mixtures

33 AASHTO T245 Determining liquid-plastic strength of bituminous mixture by Marshall

34 ASTM E950 Standard Test Method for Measuring the

Longitudinal Profile of Traveled Surfaces with an Accelermeter established inertial Profiling Reference

35 22 TCN 319-04 Vietnam Standard for advanced Bitumen Polymer

36 Manual MS-2 American Asphalt Institute

37 Policy for fine-grained asphalt concrete layer, Japan Road

38 Activity of void asphalt on expressway, Japan Highway Public

Unless otherwise specified or approved by the Engineer, equipment used for construction of bituminous pavement shall comply with the following specifications:

The distributor must be self-powered and equipped with pneumatic tyres designed to ensure that the load on the road surface does not exceed 100 kilograms per centimetre of tyre width It should be constructed and maintained to apply bituminous materials uniformly across a variable surface width of up to 5 metres, at controlled rates ranging from 0.2 to 3.0 litres per square metre, while maintaining consistent pressure and allowing for a maximum variation of 0.1 litres per square metre from the specified rate.

Distributor equipment must feature instruments that accurately measure low travel speeds, the flow rate of bituminous material through nozzles, tank contents temperature, and pressure These instruments should be positioned for easy readability by the operator during distributor operation.

The distributor must feature a dedicated power unit for the pump and fully adjustable circulation spray bars, both laterally and vertically An experienced operator, positioned at the rear of the distributor for optimal visibility, will control the spray bars Additionally, the distributor should include one or more hand-operated lances for spraying in areas that are not reachable by the main spray bars.

This shall be of the oil jacket type or else incorporate an automatic agitator to prevent local overheating of the material The heater should incorporate a thermometer.

The Bituminous Concrete batching plant must include adequate storage space for each aggregate size, ensuring they are kept separate until they reach the cold aggregate feeding system It is essential to maintain a neat and orderly storage yard, with separate bins that are easily accessible for sampling.

Bituminous mixture preparation plants must meet all specified requirements, with scale regulations applicable solely when weight proportioning is employed Furthermore, batch-mixing plants are also subject to these standards.

GENERAL SPECIFICATIONS 05200 - 29 of 54 conform to the requirements under (ii); and continuous mixing plants shall conform to the requirements under (iii).

Mixing plants shall be of sufficient capacity and coordinated to adequately handle the proposed bituminous constructions.

Plant scales must be accurate to within 0.5 percent of any load and sensitive to half the minimum gradation, not exceeding 3.5 kg Poises should be lockable to prevent unauthorized adjustments Alternatively, the Contractor may use an approved automatic printer system to record the weights of delivered materials, provided it is integrated with an approved automatic batching and mixing control system Each load must be accompanied by a weight ticket Public weighing facilities can be utilized if they are tested and sealed by local authorities, pending the Engineer's approval of the weighing procedures.

To ensure optimal preparation of bituminous material, storage tanks must be equipped with heating systems that maintain the required temperatures without direct flame contact, utilizing steam coils, electricity, or other approved methods Additionally, a well-designed circulating system is essential for maintaining proper and continuous circulation of the bituminous material throughout the operation period It is also important to include provisions for measuring and sampling the contents of the storage tanks.

To ensure consistent production and temperature, the plant must be equipped with precise mechanical systems that uniformly feed aggregates into the drier.

The plant must be equipped with a drier or multiple dryers that continuously agitate aggregates throughout the heating and drying process For cold-type bituminous mixtures, it is essential to provide equipment for mechanically cooling the dried aggregates to the specified temperature for cold mixtures, ensuring the system can supply adequately prepared material for the mixer to function at full capacity.

Plant screens must be installed to effectively screen all aggregates to the required sizes and proportions, ensuring they exceed the full capacity of the mixer for optimal performance.

The plant must feature storage bins with adequate capacity to support the mixer at full operation, organized into a minimum of three compartments to ensure proper separation of mineral aggregate fractions Dedicated dry storage is required for filler or hydrated lime, with equipment to facilitate feeding these materials into the mixer or weighing hopper Each bin should include overflow pipes to prevent material backup and individual outlet gates designed to eliminate leakage when closed, ensuring quick and complete operation Additionally, bins must allow for easy sampling and be equipped with tell-tale devices to monitor aggregate levels at the lower quarter points.

To ensure the proper integration of bituminous material in the mix, it is essential to implement satisfactory methods, such as weighing or metering, that adhere to specified tolerances Additionally, provisions must be established to monitor the quantity or flow rate of bituminous material entering the mixer.

Tiêu đề	Foundation & Pavement Structure
Thể loại	general specifications

Định dạng
Số trang	54
Dung lượng	414,5 KB