The ratio of aggregates, cement and water was determined by design mix concrete form in achieving the desired strength of concrete. In order to simulate actual site conditions, only the top-as-cast face of the samples was left exposed to the climatic conditions. 0.6.

Chemical composition and physical properties of some used cementitious materials. The beneficial effects of preventing moisture loss and water-curing are directly observed in the test results. limitations and construction project This paper presents the effects of silica fume on compressive strength, splitting tensile strength, resistance against chloride penetration and water absorption of concrete. Although, HSC has a few disadvantages, it has many advantages. (centrally) The cubes should be placed correctly on the machine plate (check the circle marks on the machine). It deals with the effect of curing methods on compressive strength development of high-strength concrete (HSC).
The strength of the concretes containing fly ash or slag appears to be more sensitive to poor curing that the control concrete, with the sensitivity increasing with the increasing amounts of fly ash or slag in the mixtures. Actual curing practices had no significant effects on strength specially those samples cured in a hot dry OD.

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So at sites, we do normally test concrete at this interval. It is concluded that residual RHA provides a positive effect on the compressive strength at early ages, but the long term behavior of the concretes with RHA produced by controlled incineration was more significant. producers arbitrarily define the HSC as the concrete having the 28-day cube strength of . The influence of aggregate strength on the compressive strength of high-strength concrete is significant.

The strength of samples cured under four different curing regimes was compared with the strength results of water-cured samples, which is designated as the control regime. Noticeable difference in the influences of the curing methods was observed for indoor samples only. The water-cementitious materials ratio of all the concrete mixtures was kept constant at 0.50, except for the high-volume fly ash concrete mixture, for which the ratio was 0.35. developing countries. SUBMIT TRY MORE QUESTIONS.

A small amount of silica fume had a large positive effect on the cylinder compressive strength and tensile strength but less on the cube compressive strength, while the fracture behavior of the resulting concrete was brittle. The results obtained open an opportunity to review the present formulas relating Ec′ to fc′ recommended by some codes.The influence of cylinder size and curing on measured compressive strength was investigated for different strength concretes. Every 7 days the water should be renewed. The

To ensure the mix is achieved the design strength, few tests must be done. Sometimes due to time The

Results of splitting tensile and air permeability reveal the significance of the filler and pozzolanic effect for the concretes with residual RHA and RHA produced by controlled incineration.This investigation aims at studying and evaluating the efficiency of existing concrete curing practices in hot climates. However, concretes made with 5 and 10% CSF resulted in the least loss in strength and drying shrinkage and had a superior quality cover concrete as indicated by the 24 h water sorption test.Various combinations of a local natural pozzolan and silica fume were used to produce workable high to very high strength mortars and concretes with a compressive strength in the range of 69–110 MPa. Although, HSC has a few disadvantages, it has many advantages.

More care and more efficient curing methods and techniques should be considered when dealing with hot dry climate.This paper presents the results of an experimental investigation on the effect of different amounts of silica fume (SF) and water to cement ratios (w/c) on the residual compressive strength of high-strength concrete after exposure to high temperatures. Results indicated that the use of silica fume in concrete increased the compressive strength of concrete. concrete with compressive strength (CS) levels in the range of 50 to100 MPa, is called HSC. Sometimes due to time These facts have shown the importance of keeping the concrete moist to achieve the required strength. Increase in water-binder ratio reduced the compressive strength of concrete irrespective of the use of silica fume. Relationships for compressive strength gain are given for normal strength, high-strength, and very high-strength concretes studied, and for different curing conditions and different cylinder sizes.The effects of replacing cement by fly ash and silica fume on strength, compressive stress-strain relationship, and fracture behavior concrete were investigated. The use of high strength concrete (HSC) has been studied for many years in developed and The concrete specimens were subjected to moist curing, curing at room temperature after demoulding, curing at room temperature after two days of moist curing, and curing at 38 °C and 65% relative humidity.The compressive strength was determined at various ages, and the resistance to chloride-ion penetration was measured according to ASTM C 1202 at different ages up to 180 days. equations are determined with ANN and Regression techniques are compared and the best is Why do we test at 7, 14 & 28 days?