Behavior of the self-compacting mortar with sugarcane bagasse ash in the fresh and hardened state

V C Santos,K K Moraes,G M Balbino,R D Vanderlei,E T D F Rosina

doi:10.1590/s1983-41952019000100012

V C Santos, K K Moraes + Show 3 more

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https://doi.org/10.1590/s1983-41952019000100012

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Abstract

Abstract Self-compacting concrete (SCC) is a material with high workability and moderate viscosity when compared to conventional concrete. Due to its advantages, the SCC has been investigated in the last decades and the research studies the use of new components in its structure and the search for the improvement of its performance, both in the fluid and in the hardened state. The goal of this study was to evaluate the behavior of self-compacting mortars with limestone filler and with the addition of sugarcane bagasse ash (SBA) partially replacing the small aggregate. To reach this goal, initially, a rate of replacement of natural sand by SBA was set. Afterwards, slump-flow and funnel-V tests were carried out in order to check the behavior of the mortars in the fresh state. After checking the behavior of the mortars in their fresh state, the different mix proportions that achieved the best aspects of fluidity and viscosity was selected, and, for self-compacting mortars, specimens were molded to determine tensile strength at 28 days, and compressive strength at 7 and 28 days. The experimental analyses demonstrated an increase in viscosity and reduction in fluidity with increasing content of limestone filler, facilitating the obtaining of self-compacting mortars. Regarding the performance of the material in the hardened state, the mortars showed a slight increase in tensile and compressive strength due to the filler effect of fines. It was possible to replace 40% of the small aggregate with SBA.

Highlights

Concrete is the most widely used construction material in the world, but with all the dynamics and innovations in engineering projects, it was necessary to carry out in-depth studies on this component of civil construction, developing new types of concrete that go beyond conventional concrete such as high-performance concrete, fiber reinforced concrete, concrete with high content of pozzolanic additives, apparent concrete, white, colored, sustainable and selfsupporting concretes, among others [1]
The goal of this study is to develop mortar with self-compacting characteristics, partially replacing the small aggregate with sugarcane bagasse ash (SBA) and using the limestone filler as fine to control the viscosity
It was decided to use a higher amount of SBA increasing the use of this residue, so that all the mix proportions of mortar were generated by a proportion of small aggregate composed of 60% sand and 40% SBA

Summary

Introduction

Concrete is the most widely used construction material in the world, but with all the dynamics and innovations in engineering projects, it was necessary to carry out in-depth studies on this component of civil construction, developing new types of concrete that go beyond conventional concrete such as high-performance concrete, fiber reinforced concrete, concrete with high content of pozzolanic additives, apparent concrete, white, colored, sustainable and selfsupporting concretes, among others [1]. In order to effectively determine the proportion of constituent materials of self-compacting concrete, it is important to pay special attention to the mortar dosing, since the SCC is composed primarily of mortar and large aggregate. For this reason, it is more convenient to make the adjustments and tests in the mortar phase, which will later compose the SCC. The mortar dosing step is very important, considering that in this phase the proportions of materials must be constituted in such a way that the SCC does not lose workability Another important factor in the production of concrete is the high consumption of aggregates, among them, sand, a natural resource very exploited and used by civil construction as a small aggregate

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