consequences of sulfate attack on concrete

... subjected to external sulfate attack 5.3 Consequences of sulfate attack on the microstructure of concrete 5.4 Consequences of sulfate attack on the mechanical properties of concrete 5.5 Concluding remarks ... crystallization Bacteriogenic corrosion of concrete in waste water networks 4.13 Conditions affecting sulfate attack References Consequences of sulfate attack on concrete 5.1 5.2 Introduction External ... Known prevention techniques References Sulfate attack 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Forms of sulfate attack 4.1.1 Manifestations of sulfate attack Source of sulfates in sulfate attack 4.2.1...

Ngày tải lên: 08/08/2014, 10:23

... Consumption of concrete obviously follows cement consumption; considering these large amounts, concrete is clearly the most used construction material Sulfate attack is a generic name for a set of ... potential developments of sulfate- resisting concretes”, J of Testing and Evaluation 4(5) (September): 347–354 Lerch, W (1945) “Effect of SO3 content of cement on durability of concrete , PCA Pamphlet ... Committee for Reinforced Concrete (1989) Recommendation on the Heat Treatment of Concrete (in German), Berlin, September BRE Digest 363 (1996) Sulfate and acid attack on concrete in the ground,...

Ngày tải lên: 08/08/2014, 10:23

... deterioration of concrete properties; porosity that to a large degree depends on the original water content of the mix and on the degree of cement hydration, and controls the migration through the concrete ... Alkali-aggregate reaction Chemical attack Sulfate attack (chemical attack involving sulfates) Ingress of aggressive chemicals into permeable concrete Permeable concrete Improper processing Reaction of internal ... production Their concentration in concrete has to be limited to assure corrosion resistance of reinforcement Excessive presence of chlorides may influence the composition of the concrete pore solution,...

Ngày tải lên: 08/08/2014, 10:23

... high sulfate concentrations, and it is not only the concentration of sulfate anions per se but also the type and concentration of the accompanying cations that should be taken into consideration ... Corrosion in Concrete, E & FN Spon, London Bloomfield, J.P (1996) Corrosion of Steel in Concrete: Understanding, Investigation and Repair, E & FN Spon, London CEN (1998) CEN/TC 104/SC N 308, “Common ... by expansion and delamination of concrete (see Figure 3.3) High concrete porosity and high concentration of cracks reaching the depth of reinforcement increase also the rate of carbon dioxide...

Ngày tải lên: 08/08/2014, 10:23

... limitations of visual inspections 5.3 CONSEQUENCES OF SULFATE ATTACK ON THE MICROSTRUCTURE OF CONCRETE In Chapter 4, the consequences of sulfate attack (from internal or external causes) on the ... resistance of concrete , in E.G Swenson (ed.) Performance of Concrete- Resistance of Concrete to Sulphate and Other Environmental Conditions: A Symposium in Honour of Thobergur Thorvaldson, University of ... disintegration of concrete containing sulphate-contaminated aggregates”, Magazine of Concrete Research 28: 130–142 Schneider, U and Piasta, W.G (1991) “The behaviour of concrete under Na2SO4 solution attack...

Ngày tải lên: 08/08/2014, 11:20

... PROTECT CONCRETE AGAINST EXTERNAL SULFATE ATTACK One of the primary conditions for the proper design and erection of a concrete structure is the full understanding of all aspects of the local environment ... sulfate- bearing compounds that may later become available for reaction with cement components of the concrete mixture Quality Control is clearly one key issue in the protection of concrete ... concrete should be designed to give dense, low-porosity concrete matrix that can resist penetration of aggressive chemical species into hardened concrete Depending on the sulfate concentration...

Ngày tải lên: 08/08/2014, 11:20

... the effect of sulfate attack on service life of concrete The model is based on following assumptions: Sulfate ions from the environment penetrate the concrete by diffusion; Sulfate ions react ... caused by one mole of sulfate, reacted in m3 of concrete, Cs is the sulfate concentration in bulk solution, C0 is the concentration of reacted sulfate as ettringite, Di is the intrinsic diffusion coefficient ... expansion upon sulfate attack The model is based on the potential for expansion provided by both C3A content of the cement and the sulfate ion concentration of penetrating aqueous solutions It...

Ngày tải lên: 08/08/2014, 11:20

... Minimize Attack on Concrete by Sulfate Soils and Waters Crammond, N.J., Longworth, T.I and Sibbick, R.G (2001) “Tredington–Ashchurch Bridge on the M5: Examination of TSA-affected concrete foundations ... high porosity of the concrete resulted in excessive carbonation and chlorination Carbonation is known to affect the stability of ettringite; in carbonated parts of the examined concrete no ettringite ... importance of the usual ettringite form of sulfate attack is believed to be preconditioned by the environmental conditions and ionic composition of the ground water The adequate compressive strength of...

Ngày tải lên: 08/08/2014, 11:20

... wetting–drying cycles: This form of storage simulates conditions of cyclic migration of sulfate- containing water into concrete It results in concentration of the sulfate near the concrete surface and leads ... immersion, sulfate ions migrate into the specimen at a rate which depends on the permeability of the material and the concentration of sulfates in the solution The action of the sulfate solution ... depend not only on the binder employed, but also on the mixture proportions, details of concrete processing, and conditions of exposure to the sulfate solution Thus, standardization of these parameters...

Ngày tải lên: 08/08/2014, 11:20

Ngày tải lên: 08/08/2014, 11:20

... transmitted diseases Census of the epidemics related to the consumption of water in Oran town The consequence of the contamination of drinking waters on health is the propagation of the diseases with ... bad condition, cracking or dislocation of the joints d In the distribution network, it is the cross connection: infiltration of waste water in the drinking water network e Others: in the case of ... corrosion: by coating of the drains or by cathodic protection Restoration of the leaking joints and drains where necessary Conclusion In the prevention against water related diseases, protection of...

Ngày tải lên: 15/03/2014, 23:20

... formation The whole-cell configuration permits measurements of the effect of hormones or other electrical stimulation on all the ion channels in the cell membrane Four types of configuration of patch-clamp ... selectivity and regulation of individual ion channels The outside-out version permits study of changes occurring in response to stimulations of ion channels that are no longer part of the cell The inside-out ... investigation of action potentials, which could be influenced by the expression of Ng on this cell line, considering its possible effects on channel properties In addition, the presence of calcium...

Ngày tải lên: 30/09/2015, 06:42

... Proportions of concretes with RCA in comparison to control 67 concrete Table 3.1 Water Absorption Capacity of Recycled Concrete Aggregates 82 Table 3.2 Particle Density of Recycled Concrete Aggregate ... demolition waste made up of crushed concrete (BCA, 2008) 1.1.1 Classifications of Recycled Concrete Aggregates In Singapore, the use of concrete is guided by the code SS EN 206-1:2009 Concrete: ... Aggregate Concrete 64 2.3.1 Test Specimen Preparation 64 2.3.2 Compressive Strength of Concrete 69 2.3.3 Tensile Splitting Strength of Concrete 70 2.3.4 Flexural Tensile Strength of Concrete 71...

Ngày tải lên: 05/10/2015, 19:06

... dosage of polyferric sulfate This means that the impact of low concentration of polyferric sulfate on amoA mRNA expression is limited, and dosage of polyferric sulfate must be optimized not only ... oxidizer based on amoA mRNA The difference of the effect of polyferric sulfate on each species of ammonia oxidizer was demonstrated by T-RFLP analysis of cDNA of amoA mRNA The profiles of T-RFLP in ... correlation between mRNA detection and in situ activity of ammonia oxidation Amount of amoA mRNA Number of AOB (×107 cells mL-1) (×106 Copies PCR-reaction-1) Community analysis of ammonia oxidizer...

Ngày tải lên: 05/09/2013, 10:15

... the nation as a whole These estimated replacement costs of the physical losses are based on the assumption that the reconstruction of the World Impact of the World Trade Center Attack on New York ... retrofitted to serve as temporary office space Impact on the Office Market One of the most dramatic and surprising outcomes of the attack was on Manhattan’s (and the metropolitan area’s) office ... September 11 attack caused disproportionate job losses in low-wage industries The attack also led to a reduction in the number of hours worked A recent study of the effects of the attack on workers...

Ngày tải lên: 19/03/2014, 11:20

... Browsing medium + high (1) Comparison of the distribution of the three types of fir regeneration with the rest of the regeneration (2) Comparison of the distribution of the two Bl types with the two ... limitation and alteration in distributions of elk following the reintroduction of wolves into Yellowstone National Park, US, Oral communication, International Conference on Forest Dynamics and ... stands compared with Site Consequences of browsing on fir regeneration 179 3.4 Interactions between site characteristics The modification of regeneration composition expected due to intense...

Ngày tải lên: 08/08/2014, 00:21

... next few hours melted into an emotional blur, fueled by the local and national news descriptions, along with the personal uncertainties of locations of loved ones, families, and barely comprehending ... tank of gas and a bottle or two of water in view of the probable traffic, detours, and closings The usual 45 drive took longer than hours because of all of the diversions This was expedited only ... home to focus on the emerging yet suddenly real potential threats of bioterrorism, chemical attacks, and other weapons of mass destruction I know that these are things we must now consider, but...

Ngày tải lên: 12/08/2014, 18:21

... extent of brain edema formation Alterations of BBB permeability with subsequent brain edema formation are common features of septic encephalopathy Several hypotheses for the pathogenesis of septic ... edema formation to the disturbed integrity of the BBB Our results are consistent with previous reports on the integrity of the BBB and the role of a permeability defect in the formation of cerebral ... formation of brain edema in septic rats Magnesium administration attenuated the increased BBB permeability and caused a reduction in brain edema formation in our rat model of intraperitoneal sepsis...

Ngày tải lên: 12/08/2014, 20:20

... detailed data on age of cases and control populations and larger populations are required Careful monitoring of AS positive flocks as planned by new European approaches on the control of AS could ... Commission European: Commission Regulation (EC) No 999/2001 of the European Parliament and of the Council of 22 May 2001 laying down rules for the prevention, control and eradication of certain ... Selection Evolution 2010, 42:14 http://www.gsejournal.org/content/42/1/14 ered The consequence is that they face a risk of being placed under inadequate control measures The assumption of a common...

Ngày tải lên: 14/08/2014, 13:21

... possible over/under estimation of genetic response due to omission of dominance, common environmental effects, and/or inbreeding, the ratio of the genetic response of each model with the simplest ... Elvingson P, Johansson K: environmental components of variation in body traits of rainbow trout Oncorhynchus mykiss in relation to age Aquaculture 1993, 118:191-204 Winkelman AM, Peterson RG: Heritabilities ... 66_70 Size of full-sib family (number of fish) Figure Frequency distribution of full-sib family sizes in two populations of Coho salmon (even = 442 families; odd = 498 families) The assumptions for...

Ngày tải lên: 14/08/2014, 13:21