Effects of microsilica and polypropylene fibers on the rheological properties, mechanical parameters and durability characteristics of green self-compacting concrete containing ceramic wastes

Abstract

In the developing countries, since a major part of the urban wastes is related to the construction sector, this study has used ceramic waste (CW) as a partial substitute for natural coarse aggregates to produce self-compacting concrete (SCC), and since the latter should have enough strength and durability, effort has been made to not only examine its rheological properties and mechanical parameters, but also study the effects of microsilica (M) and polypropylene fibers (PP fibers) on its durability characteristics (electrical resistivity, ultrasonic pulse speed and volumetric and capillary water absorption). According to the results, increasing the percent CW decreases the SCC efficiency, and increasing M and PP fibers increases its viscosity and, hence, decreases its flowability and passability, but increases its resistance against segregation. In this research, CW50M10P0.15 had the highest compressive strength – an increase of about 21% compared to the control sample – and CW25M5P0.3 showed the highest tensile and flexural strengths compared to the control sample. Adding CW reduced the durability of the SCC samples slightly, but adding M and PP fibers increased it. In the electrical resistivity test, CW25M10P0.3 showed an increase of about 168% compared to the control sample. Analyzing the scanning electron microscope (SEM) images revealed that mix designs containing ceramic wastes had a stronger ITZ, and adding M made the samples denser and more coherent.