Evaluation of self-compacting soil-cement mortar (SCSC) with polypropylene fibers for susceptibility to water absorption and shrinkage

Abstract

The control of water absorption and retraction in mortars is a requirement of vertical sealing systems (SVV) in buildings, in order to avoid constructive pathologies. This work aims to analyze the influence of the incorporation of polypropylene fibers on the water absorption and shrinkage of self-compacting soil-cement mortar (SCAA) containing Civil Construction Waste (RCC) sand, for use in SVV. From a reference trace, the method consisted of carrying out laboratory tests of water absorption and shrinkage, considering the addition of polypropylene fiber in the proportions of 0.05%, 0.1% and 0.2% in relation to the total mass of the mixture. The values of water absorption by capillarity and by submersion were high, indicating that the addition of fibers did not contribute to improve these properties. The dimensional variation values were 8.6, 9.0, 7.94 and 7.54mm/m at 28 days for the reference mortars and with fibers in the proportions of 0.05%, 0.1% and 0. .2%, respectively. The incorporation of 0.1% and 0.2% fibers reduced, on average, 12% the shrinkage in relation to the reference mix, not reinforced with fibers. Despite the beneficial effect of the fibers, all mortars fall into the class of high level of susceptibility to water absorption by capillarity (>10 g/dm2/min1/2) and to cracking (>1.2mm/m). Thus, the addition of fibers in the mixtures does little to improve the reference mix in terms of the effects investigated, indicating the need for other control mechanisms in self-compacting soil-cement mortars.