Correspondence of the Ready-mixed Concrete Industry about Regulation of Drying Shrinkage Strain
By T. Yoshikane
Concrete Journal, Vol.46, No.11, Nov. 2008
- Synopsis
- The standard about the drying shrinkage strain of concrete was specified by Japan Society of Civil Engineers. Moreover, Architectural Institute of Japan is going to be specified. In the opinion from the former, it was presupposed that drying shrinkage strain was correlated with unit water volume. However, it became clear in the latest investigation and research that the contribution of aggregate is higher. It came to be pointed out that a difference arises according to the kind of rock of aggregate especially. Then, when investigated about the present condition of the ready-mixed concrete industry, the average value of the concrete using the crushed stone of the kind of various kinds of rocks except limestone was close to 800 micro, and standard deviation was proved that it is about 130 micro, and it turned out that shrinkage reduction disposal is required for many of architecture concretes. However, regulation has many problems and the consideration about the solution touches on a required matter.
- Keywords:
- ready-mixed concrete, drying shrinkage strain, kind of rock, shrinkage reduction disposal, aggregate resources, aggregate distribution, test condition
