Effect of rice husk ash and fly ash on the compressive strength of high performance concrete

Tang Van Lam,Pham Ngoc Anh,Olga Aleksandrova,Oksana Larsen,Boris Bulgakov,D Safarik,V Murgul,Y Tabunschikov

doi:10.1051/e3sconf/20183302030

Abstract

The usage of industrial and agricultural wastes for building materials production plays an important role to improve the environment and economy by preserving nature materials and land resources, reducing land, water and air pollution as well as organizing and storing waste costs. This study mainly focuses on mathematical modeling dependence of the compressive strength of high performance concrete (HPC) at the ages of 3, 7 and 28 days on the amount of rice husk ash (RHA) and fly ash (FA), which are added to the concrete mixtures by using the Central composite rotatable design. The result of this study provides the second-order regression equation of objective function, the images of the surface expression and the corresponding contours of the objective function of the regression equation, as the optimal points of HPC compressive strength. These objective functions, which are the compressive strength values of HPC at the ages of 3, 7 and 28 days, depend on two input variables as: x1(amount of RHA) and x2(amount of FA). The Maple 13 program, solving the second-order regression equation, determines the optimum composition of the concrete mixture for obtaining high performance concrete and calculates the maximum value of the HPC compressive strength at the ages of 28 days. The results containMaxR28HPC= 76.716 MPa when RHA = 0.1251 and FA = 0.3119 by mass of Portland cement.

Highlights

The concrete experts consider the last two decades of the twentieth century as decades of concrete additives
The objective of this study are mathematical modeling the effect of amounts of rice husk ash and fly ash from TPP "VungAng" on the compressive strength of high performance concrete in the form of second-order regression equations
The compressive strength high performance concrete (HPC) is measured at the ages of 3, 7 and 28 days [13]

Summary

Introduction

The concrete experts consider the last two decades of the twentieth century as decades of concrete additives. The modern technology monolithic construction, used in various countries in the world as well as in Vietnam, widely applied mineral additives in the concrete mixtures. Among these additives, superplasticizers, complex of chemical organic and mineral additives are the most popular [1]. The mineral additives are separated to fine active additives and inert additives. It is waste generated in ferroalloy and silicon production. Popular inert mineral additives is fly ash, provided from thermal power plants (FA TPP), metakaolin, fine-grained slag and pumice, especially, reusing waste from brick production, gypsum-containing waste [2]

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