Abstract
The purpose of the present study is to examine the effect of the size and type of aggregate on the size effect in the compressive strength of concrete. River sand and gravel, glass ball and an artificial lightweight aggregate were used for aggregate. The following conclusions were obtained by the experimental study. 1) The compressive strength of normal-weight concrete and glass ball concrete is closely related to the ratio of the diameter of specimen to that of aggregate (D/d) but the compressive strength of lightweight aggregate concrete is not necessarily related to the geometrical heterogeneity of concrete system expressed by the D/d ratio. 2) The compressive strength of normal-weight concrete and glass ball concrete increases with the increase of the size of specimen, provided that the value of D/d is smaller than about 8. 3) The size effect in the compressive strength of concrete is expressed by the product of the effect of D/d ratio and the size effect in the compressive strength of mortar matrix. 4) The phenomenon that the strength increases with the increase of the size of specimen is likely to result from that the total length of cracks involved in the failure process of the specimen increases with the increasing size of specimen.
