In the case of specimens with known chloride content, they had a final chloride concentration of 0%, 0.18%, 0.37%, and 0.74% with respect to the total weight of the concrete. In the case of sulphate quantification, concrete specimens had added sulphate percentages of 0%, 0.25%, 0.5%, and 1% with respect to the total weight of …
Abstract Sand contaminated with sulphates is a local problem in the Middle East Area. It is difficult to obtain well graded sand with sulphate content within the limits specified by international standards. Inter-national standard adopt different concepts in limiting internal SO 3 contents in concrete. Some standards put maximum limits for SO
Your answer regarding permissible levels of chlorides and sulfates in aggregate might be OK for Saudi Arabia but certainly not for most of the United States. …
Limits for chloride content of aggregates Chloride ion content expressed as percentage by mass of chloride ion of combined aggregate Type and use of concrete Prestressed concrete and heat-cured concrete containing embedded metal Concrete containing embedded metal made with cement complying with BS 4027 I 0.05 Concrete containing …
The main problem oflocally available sand is its contamination with sulphates. These sulphates together with the sulphates already in cement may cause internal attack on …
The specific gravity of the solution must be between 1.151 and 1.174 for sodium sulfate or between 1.295 and 1.308 for magnesium sulfate. Aggregate Sample Preparation. Selection and preparation of the aggregate sample fractions must strictly follow the procedures in the ASTM or AASHTO standard test methods.
soluble sulphate contents and drying shrinkage. Additionally in several cases the time period is reduced from which test results are to be provided. Appendix B ... as crushed gravel sand as defined in 2.3.2, as crushed rock sand as defined in 2.3.3, or as blended sand as defined in 2.3.4. 2.3.1 uncrushed or partially crushed sand
Marine aggregates are the natural sand and gravels available in the sea or dredged from seabed. Contents of chloride, sulphate and shell in the marine …
Aggregates shall be stockpiled as individual size fractions and blended in the mix so as to meet the combined gradation requirements shown in Table 4. ... Sulphate content (SO4) ‡ ... Sand & Gravel Association. T: 905.507.0711 | 5720 …
The content of chloride and sulfate in marginal aggregates presents a broad range. Previous research [20, 23, 25,32] reports values ranging between 0.1 % and 1.9 % for chloride ions and between 0. ...
Sand contaminated with sulphates is a local problem in the Middle East Area. It is difficult to obtain well graded sand with sulphate content within the limits …
It can be seen in Fig. 1 that the BS 8500 (BS 8500-1, 2006) total chloride limit for reinforced concrete that is non-heat curing and made with sulphate resistance cement (0.2) is nearly violated at mix M4 (w/c = 0.48) even though the chloride content is less than BS 882 (BS 882, 1992) standardized limits for aggregate and ASTM C 94 (ASTM C 94 ...
The combined effect of sulphates present in aggregates and high levels of chloride ions in the mixing water on some properties of concrete was studied. Different amounts of sulphates in sand (0.38, 0.50, 0.75 and 1.0% SO3) with chloride contents in water (50, 750, 1000, 3000 and 6000 p.p.m. as Cl−) were used. The compressive strength was …
This present study agreed with Al-Hubbubi S and Abbas Z [1] when made an investigation on treatment of three samples of sand with different contents of sulfate (0.3,0.8 and 3%) by washing sulfate with magnetized water with different magnetic intensities (5000 and 9000 Gauss),they conclude that the magnetic water technology …
A detailed conductivity test method for sulfate ion content in hardened concrete was designed. • The diffusion equation of manufactured sand concrete under sulfate freeze-thaw cycles is derived by proposing the limit number of freeze-thaw cycles N 0 and the limit diffusion depth X 0.. The diffusion parameter v proposed by is a new …
The present study investigates the performance of self-compacting concrete (SCC) and self-compacting sand concrete (SCSC) incorporating recycled concrete fines and aggregate under different sulphate environments. Similar mixtures incorporating natural aggregates and natural pozzolana were also tested for comparison.
Highlights Soluble sulphates (from gypsum drywall) are a limiting factor in recycling of C&DW. Various samples were artificially prepared with different gypsum percentages. The pollution potential due to sulphate and heavy metals is studied. We analyze the correlation between solubility and leaching of sulphates. As a result, a …
The durability of internally cured concrete (ICC) with silicon–aluminum based fine lightweight aggregate (FLWA) exposed to combined sulfate and wetting–drying attack were conducted through evaluating concrete mass, relative dynamic elastic moduli (RDEM), flexural strength, microstructure and erosion products, with the consideration of …
Furthermore, the acid-soluble chloride and sulphate contents of the fine and coarse fractions of the RCA were characterized according to relevant Swedish methods for aggregates, see Table 1.
Sand contaminated with sulphates is a local problem in the Middle East Area. It is difficult to obtain well graded sand with sulphate content within the limits specified by international standards. International standard adopt different concepts in limiting internal SO3 contents in concrete. Some standards put maximum limits for SO3 …
This Standard sets out methods for the determination of chloride content and sulfate content (including easily oxidizable sulfide content) of concrete and concrete aggregates. The solutions obtained from the sample may also be used to determine the acid- soluble calcium oxide content of these materials. The method of solution will react with ...
In mortars made with commercial, low C 3 A content (Ref.) sulfate-resistant cement, barium carbonate sand inhibited gypsum and ettringite formation, ... In fact, limestone aggregate, widespread in regions or countries with a limited supply of river sand and gravel [26], [27], is one of the major causes of thaumasite sulfate attack (TSA), ...
The aggregates used in the production of concrete are inert granular materials such as gravel, crushed stone, sand, slag, recycled concrete, and geosynthetic aggregates. …
Nevertheless the excavation of one of the access tunnel also showed that some materials have a sulphate content higher than those allowed by the EN 12620 to be used as concrete aggregates.
The results show that the cement mortar made with coral sand has a much better resistance to sulfate attack than that made with standard sand. Although sulfate attack happens inevitably in coral mortar, the use of coral sand can largely mitigate the loss of properties of mortar, such as strength, mass and linear change, etc.
Table 6 summarizes the chlorides and sulphates contents in NA, VRA and CRA. These values correspond to average measurements on two samples (approximately 200 g of aggregates by sample). ......
SO 4 2− dissolved more easily when the particle size of aggregate was smaller. When the SO 3 content in the sand was less than 1.5% at 56 days, all the gypsum was dissolved. That was the reason why the expansion of specimens with a smaller SO 3 content (1.25% for fine aggregate and 3% for coarse aggregate) was not significant.
The use of coral sand filler and supplementary cementitious materials partially replacing Portland cement facilitates the utilization of coral debris waste in oceanic construction as well as CO 2 emission. The effect on thaumasite sulfate attack by coral sand powder is compared with limestone powder since thaumasite sulfate attack has …
Moreover, sulfates are commonly formed in aggregates as a result of oxidation of original sulfides, either before or after incorporation of the aggregate into concrete. Hence, they …
The problem of internal sulfate attack in concrete is widespread in Iraq and neighboring countries. This is because of the high gypsum content usually present in sand and gravel used in concrete. Specifications usually put upper limits of SO3 content in cement, aggregate and concrete. The upper limit of SO3 content is calculated …
