The Effect Of Colloidal Nano-SiO₂ On Mechanical Properties Of Textile Reinforced Concrete

Textile reinforced concrete(TRC)composed of high performance fine grained concrete and fiber fabric,because of qualitative light,good corrosion resistance and excellent crack resistance making it have a large space in the engineering structure,Since study the mechanical properties of TRC has profound significance in it’s promotion and application.This paper based on the matrix concrete modification test and four-point bending test,illustrated the influence of different contents of CNS and steel fiber on mechanical properties.The following research results have been obtained:(1)Through CNS modification tests find that when the added content of CNS at 0～1.5%,the modified fine grained concrete can meet the requirements of the TRC matrix.Fine grained concrete used 1% CNS have the maximum compressive strength in different curing ages(7d、14d、28d、60d).When compared with the benchmarked group,it’s compressive strength increased by 23.9%、18.9%、14.9% and 19.9% respectively.The content of CNS reached 1.5%,the modified fine grained concrete have the maximal flexural strength in different ages(7d、14d、28d).When compared with the benchmarked group,it’s flexural strength enhanced 44.4%、23.5% and 23.8% respectively.(2)Carrying out steel fiber reinforced concrete mechanical properties tests discover that the steel fiber mixed with CNS make the fine grained concrete have more superior qualitity.compared with the benchmarked group.When 1% CNS mixed with 2% steel fiber,the modified fine grained concrete have the maximal compressive strength and flexural strength,which enhanced 87.6%、244.4% respectively.(3)Based on the four-point bending test of TRC thin plate,the results show that adding 2%CNS into the matrix concrete can improve the interface performance of TRC plate,and the carrying capacity,deformation capacity and bending toughness of the thin plate are greatly improved.Both CNS and short-curt steel fiber can improve the cracking load and ultimate load of TRC plate;According to the test condition,the larger the steel fiber content is,the more obvious the improvement of the bending mechanical properties of plate is.The effect of the combination of CNS and steel fiber on the flexural performance of TRC thin plates was greater than that of the former addition of CNS or steel fiber.When the content of steel fiber and CNS reached at optimal combination,the flexural performance of TRC thin plates was superior.(4)The changes of internal microstructure of Textile Reinfored Concret was analyzed by SEM test to reveal the modification mechanism of Collida Nano-Sio2 and steel fiber.The results show that the action of CNS and Ca(OH)2 generates more C-S-H gel to fill the interstices of concrete,ehich improves the interface performance between cement slurry and aggregate.The addition of steel fiber can increase the interfacial performance between the fiber mesh and concrete,thus increasing the anchorage force.