Effectiveness of calcium carbonate whiskers in mortar for improving the abrasion resistance

Abstract

Abrasion resistance is a critical parameter in the durability of cement-based materials. Calcium carbonate (CaCO3) whiskers are added into the mortar to enhance the abrasion resistance. Herein, two standards (GB/T 16925-1997 and JC/T 421-2004) were employed to evaluate the abrasion resistance of the mortar modified with CaCO3 whiskers (MMCW). The mortar abrasion resistance was characterized using the abrasion parameters such as abrasion resistance depth (D), abrasion loss (G), mass loss (ML), and abrasion resistance indices (Iα). These results indicate that the abrasion resistance of MMCW was markedly improved, and the abrasion resistance of MMCW increased with the rise in CaCO3 whiskers content. By adding different content of CaCO3 whiskers into mortar, the compressive strength (fcu) enhanced from 2.4% to 10.2%, as compared to that of the plain mortar. The bridging effect of CaCO3 whiskers prevented the cracks development, while the filling effect of CaCO3 whiskers refined the large pores. The calcium hydroxide (CH) orientation improvement effect and the dilution effect of CaCO3 whiskers limited the growth of CH hydration product of mortar, enhanced the compactness of mortar, and ultimately, improved the abrasion resistance of MMCW. An excellent linear relationship was established between the abrasion resistance and compressive strength. By comparing the experimental data with the data from the literature, the prediction model of the relative abrasion resistance parameters was obtained, which can provide a reference for studying the abrasion resistance of different cementitious materials.