Properties Of Modified Sisal Fiber Reinforced Cement Mortar

As a renewable resource,plant fiber has the advantages of low price,wide source,wide distribution,low value,and meets the development concept of energy saving and environmental protection.It also has the functions of energy saving,crack resistance,enhancement and improvement of impact performance.It has very good development prospects in application.However,the addition of ordinary fibers has some shortcomings,such as corrosion problems,adhesion problems,and water absorption problems,so I modified the ordinary fibers before adding them.Therefore,this article sets up different mix ratios to prepare modified sisal fiber cement mortar,and studies the content of sisal(0,0.55%,1% and 2%)and lengths of 0-10 mm,10-20 mm and 20-30mm)Influence on the performance of cement mortar.Then set up a control group with different dosage and length,soak sisal fiber in dilute disilane solution to prepare modified sisal fiber cement mortar,study its basic macroscopic properties and durability,and use scanning electron microscopy method The microstructure of sisal cement mortar before and after modification was studied,and its microscopic mechanism was analyzed.The research has achieved the following results:(1)Test the fluidity,water absorption,flexural strength and compressive strength of blank samples,different dosages and different lengths of sisal fiber modified cement mortar.The research shows that: under the same AE dosage,The longer the length of AE is added,the fluidity of the mortar slurry decreases.With the increase of AE content,the strength ofthe mortar first increases and then decreases.The specimen with an AE length of 20 mm has the highest strength.At the same time,in the case of the same AE length,the fluidity of the mortar gradually decreases with the increase of the AE content,and the water absorption of the slurry first increases with the increase of the AE content.Then decrease,when the AE content is 1%,the water absorption reaches the maximum.The main reason is that the shorter sisal fiber cannot form an effective network structure,which plays a good lubricating effect,reduces the gap and turbulence between the mixture,and adds liquid to the cement mortar,and the fiber length of sisal is too long,Too much,a certain degree of curling,entanglement and uneven distribution will occur during the slurry mixing process,reducing the fluidity of the slurry and affecting the mechanical properties of the slurry.The water absorption rate of sisal fiber is large,but when the length of sisal fiber is small,free radicals on the exposed surface increase,which increases the water absorption interface,and the absorbed free water content increases,which increases the water absorption rate of the mortar.(2)Conduct durability tests on blank samples,sisal fiber modified cement mortar specimens with different dosages and different lengths,including single sulfate resistance test,impermeability test,crack resistance test and coupling agent modified fiber test.The results of the single sulfate resistance test show that when the AE length is the same,the quality and strength of the cement mortar specimens first increase and then decrease with the increase of the sisal fiber content;when the sisal fiber content is the same,The quality and strength of the specimens also increased first and then decreased with the increase of the length of sisal fiber.For the impermeability test,at the same content,the impermeability pressure of the mortar slurry decreases with the increase of the AE length,and decreases with the increase of the content at the same length;when the length of the sisal fiber is constant Under the premise,it will decrease as the content of sisal fiber increases.When the content of sisal fiber is 0.5%,the impermeable pressure of the slurry is maximum when the length is 10 mm.In terms of the crack resistance of the AE mortar specimens,a small amount of short sisal fiber has a better effect on the initial crack resistance of the reinforced cement mortar.The impermeability of AE mortar specimens is weak.The addition of silane coupling agent can improve the basic macroscopic properties of the mortar such as strength,water absorption and fluidity,and durability properties such as crack resistance,impermeability,and single sulfate resistance.The addition of silane coupling agent can improve the basic macroscopic properties such as the strength,water absorption and fluidity of the mortar,and the durability of crack resistance,impermeability,and single sulfate resistance.(3)The fiber content is selected to be 1%,and the sisal fiber cement before modification and the modified sisal fiber cement mortar specimens are comparatively studied.It is found that the addition of sisal fiber can effectively fill the pores of the mortar slurry and make The internal structure of the slurry becomes denser and is scattered in the matrix resin.At the same time,the silane coupling agent is hydrolyzed to form trihydroxysilane,in which the hydroxyl group reacts with the AE group to form a strong structure,which has a good explanation for its mechanical properties and durability.