Study on Mechanical Properties of Carbon Fiber Modified Fly Ash-metakaolin Geopolymer Concrete

Abstract

Purposes Geopolymer concrete has attracted wide attention because of its high strength, good durability, low carbon, and environmental protection, but its application is restricted by the poor crack resistance and toughness. Method In this study, 10 groups of carbon fibers with varying volume contents were mixed into fly ash-metakaolin geopolymer concrete, and the effects of carbon fiber volume contents on axial compressive strength, elastic modulus, flexural strength, and the folding-compression ratio of geopolymer concrete were analyzed. Conclusions The results show that adding carbon fiber could strengthen and toughen geopolymer concrete at the same time. With the increase in carbon fiber content, the axial compressive strength, elastic modulus, flexural strength, and folding-compression ratio of geopolymer concrete all increased at first and then decreased, and the optimum carbon fiber content was 0.8%～1.0%. The improvement effect of carbon fiber on the flexural strength of geopolymer concrete was about twice that of the compressive strength. Further reference is provided for the engineering application of carbon fiber modified geopolymer concrete.

Keywords

• geopolymer concrete
• carbon fiber
• axial compressive strength
• flexural strength