aggregate quality (grain size and calcite-dolomite transition), and the X-ray fluorescence (XRF) test for elemental components of carbonate aggregate (e.g., phosphorous and clay content). A combination of these test results is used to form a quality number for evaluation of the overall quality of an aggregate.
Sulfate attack in concrete and mortar. Sulfate attack can be ''external'' or ''internal''. External: due to penetration of sulfates in solution, in groundwater for example, into the concrete from outside. Internal: due to a soluble source being incorporated into the concrete at the time of mixing, gypsum in the aggregate, for example. External sulfate attack ...
· The methods given below can be adopted to protect concrete from sulphate attack. Use of Sulphate Resisting Cement. The most efficient method of resisting the sulphate attack is to use cement with the low C 3 A content. It has been found that a C 3 A content of 7% gives a rough division between cement of good and poor performance in sulphate …
1. Scope. 1.1 This test method is for the determination of water-soluble sulfate in soils. 1.2 This test method was developed for concentrations of water-soluble sulfate in soils between 0.02 and 3.33 % sulfate by mass. 1.3 This test method does not determine sulfur in any form except as sulfate. 1.4 Some governing bodies regulate the movement ...
· The expansion value with a 0.8% sulphate content using CEM II was 1450 μm/m (taken from the trendline). This value was not reached when CEM II-SR was used, a very positive and remarkable result. Hence, the application of CEM II-SR is recommended when the sulphate content in the RA is higher than 0.8%. Download : Download full-size image; Fig. 13.
Aggregates, without mineral filler, RAP, RAS, or additives, combined as used in the job-mix formula (JMF). • LA Abrasion requirement is 5% lower than 341… • Magnesium Sulfate Soundness is 5% lower …
sulfate. The presence of calcium sulfate had little effect on the compressive strength when the stabilized soil was cured at constant moisture content, but the same material suffered a considerable loss in strength when immersed in water. Substitution of sulfate-resistant cement for ordinary portland cement did not reduce the disintegrating
Table 1 — Limits on shell content Size Limits on shell content (%) Fractions of 10 mm single size, or of graded or all-in aggregate that are 20 finer than 10 mm and coarser than 5 mm Fractions of single sizes or of graded or all-in aggregate that are coarser 8 than 10 mm Aggregates finer than 5 mm No requirement 4.4 Mechanical properties When ...
The moisture content of an aggregate is an important factor when developing the proper water/cementitious material ratio. All aggregates contain some moisture based on the porosity of the particles and the moisture condition of the storage area. The moisture content can range from less than one percent in gravel to up to 40 percent in very ...
Sulfate in concrete Excessive amounts of mobile sulfate, derived from aggregates or other constituents in concrete, can cause disruption due to expansion. BS 8110 part 1 Structural use of concrete, 1985, had a limit of 4% by mass of cement based on the total acid soluble sulfate method expressed as SO 3 (clauses 6.2.5.3).
8 Sulfate damage to concrete floors on sulfate-bearing hardcore To produce deleterious amounts of ettringite the reaction requires the presence of: • a significantconcentration of water-soluble sulfates • concrete which contains a substantial content of calcium aluminate hydrates, as is the case in concrete made with most Portland cements
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 ...
Reduce Sulphate Content In Aggregates. Aggregates of specified size are subjected to cycles of alternate wetting in a saturated solution of either sodium sulphate or magnesium sulphate for 16 18 hours and then dried in oven at 105 to 110 0 c to a constant weight.After five cycles, the loss in weight of aggregates is determined by sieving out all undersized particles and weighing.
3. Use silica free aggregates. 4. Increase fire safety of the building to reduce the spalling damage by fire. 5. Adopt correct mix design ratio of concrete. 6. Use vibrators for proper compaction. 7. Use sulphate resisting cement in the mix. 8. To avoid corrosion in reinforcement you …
· The aggregate basically rusts, and two expansive sulfate products are formed (gypsum and ettringite). Because concrete has a much lower tensile strength than compressive strength (about 10 percent), typical residential concrete of 2,500–4,000 psi (17–28 MPa) compressive strength would only have a tensile strength on the order of 250–400 ...
An Overview on Sulfate Attack. A concrete structure exposed to a rich sulfate environment or contained sulfate salts in its mix constituents (water, aggregates, or cement) can degrade rapidly and causes reduction of strength. Sulfate with the presence of water and cementitious paste will result in a process called Sulfate Attack.
· Q. We''re designing a concrete structure in Egypt, and I received test results for the aggregate to be used in the concrete. The report lists chloride and sulfate content, but I don''t know how to evaluate these numbers because ASTM C 33, "Standard Specification for Concrete Aggregates," doesn''t give limits for them.
The object of this work was to develop a green concrete with an improved sulfate resistance. In this new type of concrete, recycled aggregates from construction and demolition (C&D) waste were used as coarse aggregates, and granulated blast furnace slag (GGBS) and fly ash-based geopolymer were used to totally replace the cement in concrete.
If the water-soluble chloride ion content of the combined aggregate is known to be 0.01 % or lower (e.g., for extracted from most inland quarries), this value can be used in the calculation of the chloride content of concrete. 2. Sulfur Compounds 2.1 Acid Soluble Sulfate
· Main factors affecting sulphate attack are: 1. Type of Cement and its Content. The most important mineralogical phases of cement that affect the intensity of sulphate attack are: C3A, C3S/C2S ratio and C4AF. 2. Fly ash addition. The addition of a pozzolanic admixture such as fly ash reduces the C3A content of cement.
with an air content in the range of 3 to 6 percent contains from 400 to 600 billion air bubbles. Choosing the amount and means by which air is to be added to the mix depends on a great number of va ri a b l e s. (In some areas the natu-rally occurring fine aggregate con-tains organisms which add 4 to 5 p e r cent accidental air to the mix.) In
Reduce Sulphate Content In Aggregates. Mechanical Properties Of Recycled Aggregates Concrete . Aggregates content is a factor which has direct & far reaching effects on the both quality & cost of concrete unlike water and cement, which do not alter any particular characteristics except in the quantity in which they are used, the aggregate ...
· The methods given below can be adopted to protect concrete from sulphate attack. Use of Sulphate Resisting Cement. The most efficient method of resisting the sulphate attack is to use cement with the low C 3 A content. It has been found that a C 3 A content of 7% gives a rough division between cement of good and poor performance in sulphate waters.
sulfate-resistant concrete: a maximum limit for the water to cement ratio to get a dense matrix that improves concrete transport properties; and the use of sulfate-resistant cement (with a low C. 3. A content) to reduce the mineral source for the chemical reac-tion leading to ettringite formation.
The aggregates are usually washed and graded at the pit or plant. Some variation in the type, quality, cleanli-ness, grading, moisture content, and other properties is expected. Close to half of the coarse aggregates used in portland cement concrete in North America …
1% and 0.015% of chloride content are set for non-structural and pre-stressed concrete elements respectively [28]. (h) Sulphate content may give rise to expansive disruption of concrete. Some types of sulphates in recycled aggregate present as cement hydrates in the hardened concrete or
Treatment of Sulfate-Rich Soils and Bases 3-3 TxDOT 09/2005 Section 2 Risk Assessment Sulfate detection prior to specifying and constructing calcium treated soils is the only means of prevention of sulfate-induced heave. The following is a method to estimate the potential risk for sulfate heave on a …
· Internal sulfate attack occurs when a source of sulfate is incorporated in the concrete when mixing like excess gypsum in cement, sulfate in the aggregate…
the weight lost against the original weight of the sample. The lower the value, the more abrasion resistant the aggregate is. Resistance to chemical degradation Magnesium sulphate soundness test ( MS ) – This test measures how resistant an aggregate is to chemical weathering and can be carried out on different aggregate sizes.
Reduce CHO Cell Aggregation Chinese Hamster Ovary (CHO) cells are widely used in large-scale culture. These cells have conventionally been grown as attached cultures, but they will also grow in suspension, a property which has allowed for relatively simple scale up …
recycled aggregates is higher than the thresholds fixed by the French standards, according to which the absorption coefficient must be lower than 5%. The sulphate content of aggregates coming from building demolition wastes is higher than that of aggregates coming from reinforced concrete and cement treated materials due
· Both methods to measure the solubility are determined gravimetrically and the sulphate content is expressed as percentage of sulphur trioxide by mass of the aggregate (% SO 3). 3.2. Leaching test: compliance batch test EN 12457-3. Once the solubility of the sulphate ion had been analysed, the leaching behaviour was studied, as it is described ...
· Determination of Soluble Sulphate Content Purpose Sodium sulphate is present in some soils. The salt is easily hydrated and dehydrated under the influence of climatic changes. There are enormous volume changes during this process of hydration and dehydration, which influence the engineering properties of soils. Procedure Take the soil sample in a state in which […]