Desenvolvimento e caracterização física e mecânica de compósitos cimentícios reforçados com tecido têxtil de fibras de algodão

Abstract

In the present study the development and characterization of cementitious composites reinforced with cotton textile fabric was carried out. The composites were produced from cementitious matrix, constituted by cement CP II E-32, metakaolin, sand, water and superplasticizer, trace 1: 1: 0.4. The cementitious matrix was made with partial Portland cement by 50% of metakaolin with the proposition to reduce the quantity of calcium hydroxide. The textile fabric was characterized by water absorption, X-ray diffraction (XRD), thermogravimetry (TG) and scanning electron microscopy (SEM) tests. The cementitious laminates produced were reinforced with cotton fabric with volumetric fractions of 2, 3, 4 and 6%, they were evaluated at 28 days by means of physical and mechanical tests. For most of the experimental conditions, the composites presented a “strain hardening” behavior, with formation of multiple cracking, with increase in the strength, deformation and tenacity, as the fiber content increased. The composite with a 6% fiber content presented the maximum tensile stress of 7.26 MPa, with on average 23 cracks in the middle third of the sample, and about 5.86 MPa with averge of 57 cracks, subjetcted to flexural and tensile loads, respectively. Analyzing the results, it was concluded that the fiber used presents a potential use as reinforcement of cementitious laminates, forming composites with good physico-mechanical properties.