PROPRIEDADES MECÂNICAS E ABSORÇÃO DE ÁGUA DE UM COMPÓSITO CIMENTÍCIO COM ADIÇÃO DE POLÍMEROS SUPERABSORVENTES

Abstract

Mortars are versatile cementitious composites used by the civil construction industry, the study of their pathologies and the search for technologies to improve their mechanical performance is in evolution. With this purpose, superabsorbent polymers – PSA are being added in mortars to optimize these composites in an attempt to provide humidity to the cement, improve its hydration, and minimize phenomena such as shrinkage, which usually cause cracking. Therefore, this preliminary study characterized superabsorbent polymers in terms of their granulometry, absorption capacity and produced six mixes of mortars divided into two reference mixtures, with a water/cement ratio of w/c=0.55 and w/c =0.6. For each mixture, PSA contents of 0.2% and 0.3% were added in relation to the cement mass. Mortar test specimens were subjected to mechanical tests, water absorption, and scanning electron microscopy. Mortar test specimens with a PSA content of 0.2% obtained better mechanical performance in traction by diametral compression concerning the reference mortar at more advanced ages. The water absorption in mortar test specimens with the addition of PSA was higher than in the reference mortars. The micrographs show that there was no PSA agglomeration, so the pores formed by the decrease in PSA size were not connected. The results indicate the possibility of using PSA in mortars and point to the need for studies with different techniques and contents that prove its performance as an internal curing agent of the cement to contain cracks.