EFFECT OF THE ADDITION OF SILICON CARBIDE PARTICLES ON THE MECHANICAL RESPONSE OF CONVENTIONAL PORTLAND CEMENT PAVERS

Abstract

The mechanical behavior of conventional Portland cement paver mixes with and without silicon carbide (SiC) particle reinforcement was studied. The SiC used in this work was obtained from sequential thermal processes of calcination of wood residues and infiltration of silicon metal in carbon powder. For a first batch of paver mixes, controlled amounts of SiC particles were added to Portland cement paver mixes, the amounts added were 0, 2, 4, 6, 6, 8 and 10 % by volume, which replaced equivalent volumes of fine sand. In a second batch of paver mixes, volumes of SiC particles partially replaced equivalent amounts of Portland cement, keeping constant the volume of fine sand added to the mixes. From the study, it was confirmed that (i) the average maximum compressive strength increased progressively with increasing amount of SiC added to the mixes, changing from 28 to 34 MPa when 0 and 10% by volume of SiC particles were added to replace fine sand, respectively; and with a curing time of 14 days and (ii) the average maximum mechanical resistance to compression decreased progressively when increasing the amount of SiC added to the mixtures, changing from 48 to 35 MPa when 0 and 10% by volume of SiC particles were added to replace Portland cement, respectively; and with a curing time of 28 days. On the other hand, the microstructural characteristics of the paver mixes studied were evaluated, in all of them the presence of two phases was evidenced, a continuous and interconnected one of Portland cement that enveloped another one of sand and silicon carbide particles. The stiffness of the materials studied was also evaluated, finding (i) a slight increase in stiffness in those materials with a higher concentration of silicon carbide particles added (when SiC partially replaced fine sand) and a slight reduction in stiffness in those materials with a higher concentration of silicon carbide particles added (when SiC partially replaced Portland cement).