Abstract
Abstract Geopolymer cementitious materials and recycled aggregate are typical representatives of material innovation research in the engineering field. In this study, we experimentally investigated a method to improve the performance of geopolymer-recycled aggregate concrete (GRAC). The recycled concrete aggregates and steel fiber (SF), fly ash (FA), metakaolin (MK), and sodium silicate solution were used as the main raw materials to prepare fiber-reinforced geopolymer-recycled aggregate concrete (FRGRAC). First, the orthogonal test was carried out to study the GRAC, and the optimal mix proportion was found. Second, building on the optimal mix proportion, the effects of the SF content on the slump, 7 and 28 days compressive strength, tensile strength, and flexural strength of FRGRAC were further studied. Finally, the microscopic mechanism of FRGRAC was studied by scanning electron microscopy (SEM). The study results indicate that the slump continues to decrease as the fiber content increases, but the compressive strength, tensile strength, and flexural strength increase to a certain extent. Through SEM analysis, it is found that SF restrains the development of cracks and improves the strength of concrete.
Highlights
With the growth of the global population and the acceleration of urbanization, the development of the construction industry has been greatly promoted, but this has exacerbated the problem of environmental pollution
It can be found that the order of factors affecting the compressive strength of 7 days geopolymer-recycled aggregate concrete (GRAC) is sand ratio < aggregate cementitious material ratio < modulus
This study has explored the optimum mix proportion of fly ash (FA)–MK geopolymer recycled concrete through orthogonal design
Summary
With the growth of the global population and the acceleration of urbanization, the development of the construction industry has been greatly promoted, but this has exacerbated the problem of environmental pollution. Geopolymers are mainly derived from industrial production wastes. Combining these raw materials rich in silicon and aluminum compounds, such as FA, MK, etc., with an alkali solution will cause polymerization. On the other hand, recycled aggregate concrete (RAC) can solve the problem of construction waste disposal. The. Experimental study of steel fiber-reinforced geopolymer-recycled concrete 579 test blocks of waste concrete are usually crushed, cleaned, graded, and mixed according to a certain proportion to prepare recycled concrete aggregate (RCA). A combination of GPC and RAC can greatly solve the pollution problem in civil engineering construction. This article presents using steel fiber (SF) and FA–MK matrix geopolymer cementing material to prepare fiber-reinforced geopolymer recycled aggregate concrete (FRGRAC). It is expected that the results from this study can help establish a foundation for the FRGRAC application in engineering practice in the future
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