SECURITY AND SAFENESS VRAMP – CONTRACT PACKAGE RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA STRENGTHENING BASE COURSE TABLE OF CONTENTS I MATERIAL II CONSTRUCTION EQUIPMENT III CONSTRUCTIO[.]
VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA STRENGTHENING BASE COURSE PHUONG THANH TRANCONSIN VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA TABLE OF CONTENTS I MATERIAL II CONSTRUCTION EQUIPMENT III CONSTRUCTION METHOD IV INSPECTION AND ACCEPTANCE OF THE STRENGTHENING BASE COURSE PHUONG THANH TRANCONSIN VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA I MATERIAL Reference Standards The lastest version of the below standards shall be applied for the materials in this section: - Specifications of design, construction and acceptance of the cold in-place mining strengthening mixture with bitumen foam and cement in highway structure according to the Decision No 3552/QD-BGTVT dated 22/9/2014 of the Ministry of Transport - 22 TCN 333-06 The process of soil compaction, chipping in the laboratory - TCVN 8818-2011 Cut-back Asphalt — Specification and test method - TCVN 8860-2011 Asphalt concrete - Test method - TCVN 7572-2006 Aggregates for concrete and mortar -Test methods - TCVN 7493-2005 Bitumen – Specifications - TCVN 7494-2005 Bitumen - Sampling method General Requirement for Materials Materials of the strengthening base course is the materials of existing pavement structure within scarification and strengthening area in which the aggregate composition and humidity at site are the important factors in need of being determined to serve for the design of mixture meeting regulations in Table and Table (as below) enclosed with the Decision No 3552/QD-BGTVT dated 22/9/2014 of the Ministry of Transport In case of necessity, the aggregate with different particle size can be added to the materials of the strengthening base course 2.1 Additional aggregate (if any) The additional aggregate is usually added to meet one or several aims as follows: 2.2 - To change the aggregate composition of the materials of the strengthening base course; - To change the physical characteristic (strength, deformation) of the strengthening materials; - Quantity and type of additional aggregate (if any) shall be determined in the mixture design time following the guidance in Table and Table (as below) Foam bitumen The bitumen for foaming has to meet the requirements in the Specification TCVN 7493:2005 - Technical requirements and technical criteria as prescribed in the Circular PHUONG THANH TRANCONSIN VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA No 27/2014/TT-BGTVT dated 28 July 2014 issued by MOT regarding the management of quality of bitumen material used in the transport construction - The temperature of bitumen before foaming shall be 160°C -180°C - Foaming character of bitumen: All bitumen used for foaming shall be tested in the laboratory to determine the foaming characteritstics through the expansion ratio (R) and half life period (1/2) to meet the minimum requirements in Table Table Limit foaming character Temperature of strengthening mixture 10°C to 25°C More than Minimum expansion ratio, ER (times) 10 Shortest half life period, 1/2 (second) Test method 25°C Appendix A -Specifications of design, construction and acceptance of the cold inplace mining strengthening mixture with bitumen foam and cement in highway structure - Foam bitumen content should be used for the strengthening base course of the asphalt concrete pavement follows Table - Optimal foam bitumen content is determined through the design of the strengthening base course Table Recommended foam bitumen content Screened grain (%), sieve size 4.75 mm 10 3.0-4.0 3.0-5.0 2.0-3.0 5.0-7.5 2.5-3.5 VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA Screened grain (%), sieve size 4.75 mm 2.3 7.5- 10.0 % Foam bitumen calculated following dry mixture volume 3.0-4.0 >10 3.5-4.5 0.075 mm Cement Cement used for mixing with the strengthening base course has to meet technical specifications which are appropriate with regulations in current Vietnamese Standards (TCVN 2682:2009 or TCVN 6260:2009) The normal cement content is 1% dry aggregate content to increase the bitumen adhesiveness with the aggregate, thè bitumen allocation in the mixture; to reduce elastic factor of natural materials; to improve the hardness of the mixture and the adhesion speed of compacted mixture The cement content does not exceed 1.5% of the mixture without the grain smaller than 0.075mm 2.4 Water Water used for damping and foaming shall have the technical characteristic in accordance with TCVN 4506:2012 2.5 Other additional agents (if any) The additional agents can be used to help with the foaming of bitumen However most of the additional agents shall be put into bitumen before being heated to the treated temperature because they are very sensitive with the heat, that means they only have effect in short time in the condition of high temperature to promote the foaming additional agent benefit, and the bitumen shall be used within some hours after being mixed with them, Type and ratio of additional agents for use shall be accepted by the Engineer before consttuction Technical specifications of cold scarification and strengthening material mixture The materials of the strengthening base course shall satisfy the criteria in Table STT Technical PHUONG THANH TRANCONSIN Regulations Test method VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA Sample Marshall D=100m m Sample Proctor D=152mm (*) Strengthening asphalt pavement with crushed stoned aggregate 250-600 120-250 Strengthening of crushed stone aggregate layer 200-500 120-200 Strengthening of natural aggregate layer 150-450 80-150 specifications Indirect tensile strength (dry ITS) at 25°C, kPa Ratio of TSR = wet ITS / dry ITS Strengthening asphalt pavement with crushed stoned aggregate 0.8-1.0 Strengthening of crushed stone aggregate layer 0.6-0.9 Strengthening of natural' aggregate layer 0.3-0.75 Unconfined Compression Strength (UCS) ≥700 kPa Appendix B -Specifications of design, construction and acceptance of the cold inplace mining strengthening mixture with bitumen foam and cement in highway structure (*)The test with sample Proctor shall only applied for the section with designed ESAL >5.106 andpavement design with method TG2 Samples are stored and tested PHUONG THANH TRANCONSIN VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA at the balance moisture determined in the Appendix B (the Specification) Aggregate of the strengthening base course: Aggregate of the strengthening base course shall meet requirements in the Table before being mixed with bitumen foam and cement Table Aggregate contents required for the strengthening base course Square sieve size (mm) Screened grain (% volume) 50 100 37.5 87-100 25 75-100 19 67-94 12.5 55-85 4.75 35-67 0.6 14439 0.075 4-20 If the design and actual aggregate contents not meet requirements in the Table and are not good enough for mixing (with additional aggregate), the design of the aggregate shall follow the guidance of the Engineer II CONSTRUCTION EQUIPMENT Before construction, the Contractor shall submit the strengthening base course process for the Engineer’s approval, including: - Specialized strengthening base course machine - Specialized hot bitumen carrier and supplier truck - Specialized cement spreader - Motor grader - Rollers: Sheep-foot roller, Vibration roller, Rubber-tyred roller, steel-wheeled roller - Water tank truck The specific requirements and technical features of each equipment as below: Specialized milling and strengthening machine The machine shall be auto-action and designated to scarify the materials in the upper layers of the existing pavement structure, mix them with the additional materials (if PHUONG THANH TRANCONSIN VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA any) which are placed on the existing pavement in to become a homogeneous material layer The machine shall meet the requừed content and homogeneous aggregate in just one time of passing and shall have the following characteristics: - Minimum capacity is 400 horse power - To be designed.and manufactured at factories, with sufficient of monitoring documents and origin certificates - Drum cutter shall have minimum working width of 2m with the capacity of changing the 04 rotating speeds (112-126-160-181 cycles/ minute) The machine shall have the sừengthening capacity to the required depth in only one time of passing - The machine shall have balanced control system to maintain the depth of scarification in the limit of error ± 10mm of the requhed depth throughout the continuous operation time; - Drum cutter shall rotate following the cutting dừection up with the minimum speed of 112 cycles / minute; - All of the spray system of foam bitumen and water combined closely with the milling machine shall be controlled by the microelectronic set to control the flow speed corresponding with moving speed of the machine The spraying system shall have capacity to change the spraying volume in a wide range of - 500 kg/ minute, equivalent to the foam bitumen content of - 5%; - The machine shall have capacity of supplying the foam bitumen with the requfred speed throughout the operation time; - The machine shall have capacity to control the ratio of foam bitumen for the suitable with the moving speed of the machine and volume of the strengthening base course materials; - The machine shall have capacity of supplying the homogeneous foam bitumen; - The machine shall have the display device on it to monitor the supplying duration of foam bitumen during the operation time; - The machine shall have on it the temperature control device and pressure valve of the supplying line of foam bitumen for the aim of quality control; - Materials after being mixed shall be out of the mixing room continuously and not be layered Specialized cement spreader PHUONG THANH TRANCONSIN VRAMP – CONTRACT PACKAGE:RAP/CP15 – MAINTENANCE OF NH6 FROM KM193÷KM233 IN SON LA It is the tank truck equipped with the spreading equipment which can measure out exactly the cement quantity to spread into thin layers with the permissible error of 5% of the requừed quantity on a certain unit area of the existing pavement Hot bitumen carrier truck It shall be the specialized truck with the connecting pipe behind and the coupling that can be dragged from the front and pushed from the behind - The capacity of truck is around 10,000 liters - 15,000 liters or at the request of the Engineer - All of the tank trucks connecting to the milling and strengthening machine shall not have leak, including the tank and connecting pipe system with the machine Drip of water (or bitumen) though does not have clear harm during the strengthening time but it leaves the “soft points” on the pavement - Each of foam bitumen containing tank shall be equipped with: An active thermometer to show the temperature inside of 1/3 container; An admission valve behind, with the inside dimension at least of 75mm to discharge the bitumen out of the container A cover for heat insulating around; An oil or gas system of heating with the capacity to increase the temperature to at least of 20°C in one hour Rollers The roller for use is the self-moving one The roller group shall include at least the types as follows: Sheepfoot roller: The sheepfoot roller is the initial and primary rolling on the high range The static quantity of the roller for use shall be determined by the thickness of the strengthening material as the Table with the vibration force from 25ton to 35ton Table Selection of static quantity of roller depends on the thickness of the compacting layer Thickness of the compacting layer Minimum static quantity of roller (ton) 10 3.0-4.0 3.0 -5. 0 2.0-3.0 5. 0-7 .5 2 .5- 3 .5 VRAMP – CONTRACT PACKAGE:RAP/CP 15 – MAINTENANCE OF NH6 FROM KM193÷KM233... base course Square sieve size (mm) Screened grain (% volume) 50 100 37 .5 87-100 25 75- 100 19 67-94 12 .5 55- 85 4. 75 35- 67 0.6 14439 0.0 75 4-20 If the design and actual aggregate contents not meet... (%), sieve size 4. 75 mm 2.3 7 .5- 10.0 % Foam bitumen calculated following dry mixture volume 3.0-4.0 >10 3 .5- 4 .5 0.0 75 mm Cement Cement used for mixing with the strengthening base course has to meet