Research On Mechanical Property Of Bentonite-PVA Fiber Cementitious Composite

In this paper,bentonite-PVA fiber cement-based composites were prepared by adding bentonite into cement-based composites by utilizing water retention,thickening and cohesiveness of bentonite.The working properties and mechanical properties of PVA fiber cement-based composites with different bentonite content were studied,which provided a scientific basis for its application in engineering.The main research contents are as follows:(1)Based on water-binder ratio,bentonite content and fiber content,orthogonal experimental design was carried out to study the performance of cement-based composites,and the performance of bentonite-blended PVA fiber cement-based composites was compared with that of non-bentonite-blended PVA fiber cement-based composites,and the change rule of its performance was studied.The addition of bentonite can effectively shorten the initial setting time of PVA fiber cement-based composites,and the addition of bentonite can shorten the initial setting time of PVA fiber cement-based composites by 30.9%~41.9%compared with the non-addition of bentonite,the consistency of bentonite-PVA fiber cement-based composites was in the range of 55-80 mPa.s,and the slump of bentonite-PVA fiber cement-based composites was in the range of 70-140 mm.(2)The mechanical properties of bentonite-PVA fiber cement-based composites were studied.With the increase of curing age,the flexural and tensile strength of bentonite-PVA fiber cement-based composites increased,but the compressive strength decreased.With the increasing substitution rate of bentonite,both flexural strength and tensile strength show a downward trend.It is reasonable to control the appropriate content of bentonite in the range of 10%-15%.(3)The pore structure was analyzed by scanning electron microscopy(SEM),and the hydration reaction between cement mortar and bentonite,the bonding characteristics between cement mortar and fiber,and the meso-properties of cement-based composites were studied from a meso-perspective.(4)The mechanical properties of bentonite-PVA fiber cement-based composites were predicted.Based on the existing experimental data,the mechanical properties of bentonite-PVA fiber cement-based composites were predicted by using BP neural network.