Evaluation of technical and economic desirability of high-performance self-compacting concretes containing metakaolin, micro silica and fly ash

Document Type : Research Paper

Authors

1 Ph.D. student, Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

2 Associate professor, Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran

3 Assistant professor, Department of Civil Engineering, Tehran Markazi Branch, Islamic Azad University, Tehran, Iran

10.22124/jcr.2021.19094.1485

Abstract

Self-compacting concrete (SCC) has more plastic viscosity and less yield strength due to using more fillers and superplasticizers. In order to achieve performance SCC, in addition to rheology, it is necessary to improve the mechanical properties and durability of concrete. Therefore, the amount of cement should be increased or cement replacement materials should be used. This increases the cost of one cubic meter of concrete and reduces the tendency to use it. In this research, by making 20 mixes of performance SCC, mechanical properties were determined by performing tests of compressive strength, tensile strength and elasticity modulus, and durability properties by tests of water penetration depth, rapid chloride penetration and sulfate resistance. Basically, the degree of technical desirability of concretes was determined. Also, by examining the cost price of one cubic meter of concrete, the economic and technical-economic desirabilities of the concretes were calculated. The results showed that the application of pozzolans in performance SCC reduced the technical desirability due to mechanical properties about 40%, but the technical desirability due to durability increased significantly, so that at the age of 91 days, about 5 times has become more. Accordingly, the final factor of technical desirability in SC mixtures of research is at least 26% and at most 250% more than the reference concrete. Due to the higher price of pozzolanic materials than cement, with the increase in the replacement rate of pozzolans, the economic desirability factor decreased to more than 50%, but the technical-economic desirability factor improved to about 60%.

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