Study of the influence of the replacement of portland cement by red ceramic residue in the manufacture of fiber cement boards

Abstract

Currently, the waste of the red ceramic industry presented as a potential alternative for use in cementitious matrices such as mineral or pozzolan addition of low reactivity. This study had as objective evaluate the influence of partial replacement of CP V ARI cement by the red ceramic industrywaste on fiber cement plates. The cement was replaced to volume in the percentages of 0, 15, 25 and 50%. These combinations were reinforced with cellulose and polypropylene (PP) fibers. The investigation was perform tests including X-ray diffraction, scanning electron microscopy and thermogravimetric Analysis. Moreover, mechanical flexural strength tests of the boards were performed on samples produced based on a suction and pressing process. All test were performed with samples at 28 days of hydration. The results of the microstructural characterization showed a reduction of calcium hydroxide as the RCV content increases, due to the consumption of this com-pound as result of the pozzolanic reaction, C-S-H peaks were also observed in all mixtures. Considering the results of the flexural mechanical properties, all percentages of substitution presented satisfactory results in accordance with the NBR 15498 standard referring flexural strength for use on external facades.