Effect Of Internal-Curing Materials With Air-Entraining On Properties Of Concrete

As we all know, there are artificial conservation demanding and long curing period after the concrete forming. Therefore, super-absorbent polymers as the internal-curing materials within concrete. Play the role of the internal conservation and air-entraining effect of both, this can reduce the external conservation and the concrete can be achieved requirements without artificial conservation.This paper select two materials: material A and B. They have great difference between the water absorption capacity and water holding capacity, to explore both the air-entraining effect and internal-curing consequent in the concrete. First, with square hole sieve filtration water absorption capacity and water retention of internal-curing materials in the experiment. Second, the conservation of materials used in cement paste, determination of pore structure parameters. Finally, the materials applied in concrete to study the conservation of materials within the compressive strength of concrete after mixing, the internal pore structure and frost resistance, internal relative humidity and autogenous shrinkage rates. Frost resistance of concrete with single freeze-thaw method. Since the contraction of the use of vertical cylinder mold, each specimen corresponds to a dial indicator measured shrinkage values.The results showed that: water absorption of the internal-curing material A is 750.0g / g (1h), released water rate of 38.2% within 24h; water absorption of the internal-curing material B is 265.0g / g (1.5h), released water rate of 23.4% within 24h. Internal-curing materials have played a significant air-entraining effect in cement paste and concrete. The internal-curing material A has decreased frost resistance of concrete significantly, the material B on frost resistance of concrete to improve a great role in promoting. After the incorporation of conservation materials within the conservation effect is remarkable; farther away from the dry surface of test hole, the internal relative humidity drops, the more slowly; the same age as the test hole location relative humidity within the growth of the first rapid decrease, 10d after the change gradually leveled off. Incorporation of the material within the conservation inhibit the role of autogenous shrinkage of concrete. Since the relative humidity inside the concrete and there is a correlation between the rate of contraction. Obtained by curve fitting of concrete from shrinkage and internal relative humidity between the values were significantly lower correlation, fitting the latter two meet the following formula:ε=a + b(△RH) + c(△RH)2. After the mixed material within the compressive strength of concrete conservation group compared with baseline decreased 5.0% ~ 22.4%.Water absorption capacity is moderate, water retention is more suitable as a good material entraining concrete curing materials based applications.