SAP对火山灰混凝土收缩性能的改善作用

Improvement of SAP on Shrinkage Performance of Pozzolanic Concrete

研究了高吸水树脂(SAP)对C40和C60火山灰混凝土自收缩、干燥收缩及水分损失率的影响,并探讨了SAP对火山灰混凝土收缩性能的作用机理.结果表明:SAP内养护可以显著降低C40和C60火山灰混凝土的自收缩,提高火山灰混凝土的抗裂性,且内养护减缩率与内养护水胶比呈正比关系;SAP内养护增大了火山灰混凝土的干燥收缩和水分损失率,且增大幅度随着内养护引入水量的增加而增大;根据干燥环境中火山灰混凝土的水分损失率与干燥收缩的拟合关系得出了火山灰混凝土产生干燥收缩时的临界水分损失率;虽然SAP内养护增大了火山灰混凝土的干燥收缩,但其总收缩较基准混凝土显著降低.

The influence of internal curing technology by super absorbent polymer(SAP)on the properties(e.g.autogenous shrinkage,drying shrinkage and water loss rate)of C40 and C60 concrete with natural volcanic ash were analyzed.The results show that internal curing with SAP can significantly reduce the autogenous shrinkage of C40 and C60 pozzolanic concrete,improve the crack resistance of pozzolanic concrete,and the fitting relationship between autogenous shrinkage reduction rate and internal curing water binder ratio is obtained.Internal curing with SAP increases the drying shrinkage and water loss rate of pozzolanic concrete.Increase in amplitude is enlarged as the quantity of internal curing water increases.Based on the fitting relationship between water loss rate and dry shrinkage of pozzolanic concrete in dry environment,the critical water loss rate of pozzolanic concrete during drying shrinkage is obtained.Although internal curing increases the drying shrinkage of pozzolanic concrete,the shrinkage performance is superior to that of control concrete.