Abstract
Properties of expanded shale aggregates are discussed in the preceeding report. This report describes results of studies on lightweight concretes made with these aggregates. In addition to 2 expanded shale, normal sand-and-gravel and Haruna pumice are used for a comparison. 2 kinds of concretes, high and low slump, are mixed. One of their slump is 19cm, for normal cast-in-place concretes and another in 5cm, for pre-cast concretes. Cement contents, fine-to corse aggregate ratio and air contents of fresh concrete are decided by trial mixes. Properties of concretes which their cement contents ranges from 250〜400kg/m^3 are tested. These tests include unit weight of fresh concretes, dryed weight, compressive and bond strength, modulus of elasticity, drying shringage and freezing-thawing resistance. Although there are some differences between 2 expanded shale concretes, test results are approximately as follows. i. These concrete weight are 1.3〜1.5kg/l and are 60〜70% of normal weight concretes. ii. These compressive strength are linear to cement contents and 150〜220kg/cm^2 concretes are gained by using 350kg/m^3 cement contents. iii. These modulus of elasticity are 1.1〜1.4×10^5kg/cm^2 and about 60% of normal weight concretes. iv. These drying shrinkage of 60 days are 0.05% and are smaller than the others. v. Freezing-thawing resistance corresponds to total water contents and one of expanded shale concrete are as strong as normal weight concretes.
