Effect of particle characteristics stress on the mechanical properties of cement mortar with coral sand

Abstract

The coral sand is widely used as a construction material in the world. The mechanical behavior of cement mortar made by coral sand would be quite different from that made by the Leighton Buzzard sand (LBS) due to the inherent properties of coral sand, such as large void ratio, irregular shape and particle breakage. The effect of particle size on the particle crushing stress and influence on the mechanical behavior of cement mortar are examined in this study. A series of single particle compression tests of coral sand particles were carried out. The results revealed that the characteristic stress of single particle for both coral sand and LBS decreased with the increasing of particle sizes. The exponent relationship between the average crushing characteristic stress and particle size was proposed. The crushing stresses of single particles were in a wide range which varied from 0.99 MPa to 38.25 MPa and 10.98 MPa to 89.41 MPa for coral sand and LBS, respectively. The uncertainly of the crushing stress for single particles was analyzed and considered as Gaussian distribution. A probability density function of characteristic crushing strengths for both coral sand and LBS particles were derived and further verified with experimental results. Finally, the cement mortar specimens with five different types of particle size distributions of coral sands were prepared and tested to investigate the effects of the particle characteristic stress on the compressive strength of the cement specimen. An exponent relationship between the compressive strength and the particle crushing strength was derived and proposed which could helpful for the concrete mix proportion design with coral sands.