Autogenous shrinkage and drying shrinkage of cement paste at early aging

The shrinkage of cement paste at early aging(7d) has been paid much attentions.Autogenous shrinkage was examined by corrugated pipe method.Autogenous shrinkage and drying shrinkage of cement paste with different W/C ratio were measured to evaluate the shrinkage at early aging.Experimental results demonstrated that corrugated pipe method could truly and directly used to examine the autogenous shrinkage at early aging compared to other methods.Since much shrinkage is neglected when autogenous shrinkage is measured after cured for 1 day,it is more reasonable to measure initial length at 10 min after initial set.Drying shrinkage based on initial length measured after cured for 3 days was not reliable because of the short aging of curing condition in many practical projects.