Influence of aggregate materials characteristics on the drying shrinkage properties of mortar and concrete

This paper presents an experimental study to clarify the effect of various aggregate materials characteristics on the drying shrinkage property in mortar and concrete specimens incorporating fourteen kinds of fine aggregate materials (standard sand, natural sand, marine sand, various kinds of slag-type sand, and various kinds of crushed sand) and three kinds of coarse aggregate materials (andesite gravel, hard sandstone gravel, and limestone gravel). The test results revealed that the characteristics of fine and coarse aggregate materials play an important role in controlling the drying shrinkage property of mortar and concrete, respectively. Limestone sand and blast furnace slag sand can restrain the drying shrinkage of mortar specimens about 22% and 30%, respectively, compared to the case of mortar incorporating standard sand. The drying shrinkage strain of concrete specimens proportionally increases with the increase of aggregate shrinkage strain, specific surface area and 6-30 nm in diameter pore volume of aggregates, which implies the significant influence of aggregate characteristics on drying shrinkage development in concrete. It was also found that the drying shrinkage property in concrete can be affected by the static modulus of elasticity and total amount of water content, in which the water absorption ratio, unit mass of aggregate and unit water content were considered. Finally, the experimental results presented are useful information for providing a good perspective for the concrete mixture design practices taking into consideration that concrete drying shrinkage could be controlled by appropriate aggregate characteristics and reducing the total amount of water content.