1. Selection of admixture for commercial concrete
The choice of admixtures for commercial concrete depends on the requirements of engineering design for the performance of commercial concrete, such as strength label, impermeability, freezing-thawing resistance, durability, elastic modulus and other physical and mechanical properties, as well as construction technology, construction season (winter or summer construction), placement and volume.In addition, but also consider the actual project to provide raw materials: cement varieties and grades, sand and stone quality.On this basis, the admixture varieties and grades that meet the use requirements are selected.When choosing admixture, the raw material that must use actual project USES carries on commodity concrete to try to match the test, and admixture USES the same kind of admixture that different manufacturer produces, according to the result of trial match from the determination from the technical, economic Angle says the most suitable admixture.
2, the admixture of commercial concrete
The optimum amount of admixture is an important factor to obtain the best technical and economic results.The optimum amount of admixture is determined by the test result of commercial concrete. The basic principle is to use the minimum amount of admixture on the premise of meeting the performance requirements of commercial concrete.The product specification that the manufacturer provides is the admixture range when some kind of admixture is used, and the reasonable admixture amount that USES unit must decide through commodity concrete try to match.Generally speaking, the compound efficient water reducer in the same water reduction rate than a single efficient water reducer admixture reduced some, the adoption of the post-admixture method can make the admixture reduced, the effect is better.In addition, the variety of cement, fineness, mineral composition and mixed materials also affect the amount of admixture.Such as: slag cement high - efficiency water reducer less than ordinary Portland cement.The cement with high surface and high C3A content should be mixed with more efficient water reducer.
