Experimental Research On Mechanical Properties And Durability Of Hybrid Fibers Light-weight Aggregate Concrete

Due to the advantages of diversified material sources, low cost and easy to shape, concrete has been widely used in national economic construction, but its defects, such as great weight and poor toughness, restrict the further development of concrete. In order to improve these defects of concrete, people are committed to looking for new materials to replace or add to concrete for a long term. A large number of studies have shown that the replacement of traditional aggregate by lightweight aggregate and incorporating fiber in concrete can effectively reduce the weight of concrete, increase the toughness of concrete, and improve the durability of concrete.Pumice is abundant in Inner Mongolia region. In this study, such regional resource advantage is closed combined with natural pumice in Jining, Inner Mongolia as the coarse aggregate of concrete. Moreover, it is focusing on the working performance, mechanical properties, anti-freezing performance, pore structure parameters and carbonation resistance performance of lightweight aggregate concrete with single addition or mixed addition of glass fiber and polypropylene fiber.In terms of mechanical performance, a research has been carried out on the influences of fiber addition on compressive strength and splitting tensile strength of lightweight aggregate concrete as well as the enhanced toughening mechanism of fibers. Meanwhile, a hybrid coefficient was used to analyze the quantitative relation between positive-negative hybrid effect of fibers and fiber addition. Finally, a constitutive relation of fiber reinforced lightweight aggregate concrete was studied to draw and analyze its stress strain curve. In terms of durability, it was first to study the mass loss of specimens and the change trends of relative dynamic elastic modulus for fiber reinforced lightweight aggregate concrete under the action of freshwater freeze-thaw cycle. Moreover.the relation between concrete pore structure and freeze-thaw cycle was explored to study the influences of fiber addition on the carbonation property of lightweight aggregate concrete.so as to fit the measured carbonation data for carbonation depth-time relation.The results show that the glass fiber and polypropylene fiber within the scope of reasonable dosage. can effectively improve the mechanical properties and durability of the lightweight aggregate concrete. and meet the needs of the general engineering.