Experimental study of the effect of silicate modulus and alkali concentration on the mechanical and fracture properties of alkali activated slag concrete at ambient temperature

Document Type : Original Article

Authors

1 Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran.

2 Associate Professor, Faculty of Civil Engineering, Noshirvani University of ‎Technology, Babol, Iran

Abstract

Alkali activated slag concrete, as a new type of concrete in which, conventional Portland cement is not used, due to various advantages such as reducing the amount of CO2 produced, the use of by-products and recycled steel industry and mechanical characteristics comparable to ordinary concrete, in The last decades have been welcomed by various researchers. On the other hand, due to the nature of concrete cracking, it seems necessary to study its fracture characteristics. Two parameters of silicate modulus and alkali concentration are the most important factors affecting the mechanical and fractur properties of this type of concrete. In this experimental study, their effect was studied. For this purpose, 16 different mixes of Alkali activated slag concrete in 4 classes of silicate modulus and 4 classes of alkali concentration and 3 ordinary Portland concrete mixes were selected for comparison. In order to obtain the fracture characteristics of the work-fracture method, a total of 95 three-point bending notched beams were prepared and tested after storage at ambient temperature at the age of 28 days. According to the results, in all values of alkali concentration, with increasing silicate modulus, the specific fracture energy increased and the characteristic length of crack decreased, and with increasing alkali concentration from 4.5 to 6.5%, in all values of silicate modulus, the specific fracture energy increased and the characteristic length of crack decreased. which indicates an increase in the brittleness of concrete. However, by increasing the concentration of alkali from 6.5 to 7.5%, an inverse trend was observed in the fracture parameters. The results showd that at similar values of compressive strength, the fracture energy of alkali activated slag concrete was higher than ordinary portland concrete and the crack characteristic length was lower.

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References

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History

  • Receive Date: 15 June 2021
  • Revise Date: 30 September 2021
  • Accept Date: 09 November 2021

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