Research On Influence Of Modified Rice Husk Ash On Damping And Strength Properties Of Cement-based Materials

This article attempts to find a way to balance the strength and damping properties of cement-based materials.The pozzolanic activity of rice husk ash is beneficial to the strength of cement-based materials.At the same time,the interfacial friction between the unhydrated portion of the rice husk ash and the cement matrix may be beneficial to increase the damping of the cement-based material.If the rice husk ash is modified to weaken the interface bond between the rice husk ash and the cement matrix,it may increase the damping of the cement-based material to a greater extent.Compared with the method of improving the damping performance of cement-based materials through the surface modification of aggregates,the interface of smaller-scale rice husk ash introduced into cement-based materials is more dispersed.This method may not significantly reduce the strength of cement-based materials.The main content of the paper is as follows:(1)Using the three methods of "vinyl triethoxysilane modification","PMMA modification","PS modification" to modify rice husk ash;combining the four methods of FTIR,TG,contact angle,SEM-EDS to test the difference between rice husk ash and three modified rice husk ash.All three modification methods can change rice husk ash from hydrophilic material to hydrophobic material.The amount of polymer on the surface of polymer-modified rice husk ash is large,and the silane coupling agent on the surface of SRHA is an extremely thin layer.(2)Applying rice husk ash and modified rice husk ash to cement mortar to test the strength and damping performance of cement mortar.The content of rice husk ash in this paper is within 18%.With the increase of RHA content,the strength and damping performance of cement mortar are enhanced.Overall,as the amount of modified rice husk ash increases,the strength of the cement mortar decreases,and the damping performance increases first and then decreases.When the dosage is fixed,the damping performance of polymer modified rice hull ash to cement mortar is higher than that of SRHA,and SRHA is higher than RHA.At the same time,modified rice husk ash will not significantly reduce the strength of ceme nt mortar.(3)Combining the three methods of XRD,TG and FTIR to analyze the effects of rice husk ash and three modified rice husk ash on cement stone hydration products.The content of calcium hydroxide in cement stone reflects the activity of rice husk ash.RHA activity is higher,SRHA activity is lower than RHA,PMMARHA and PSRHA activities are similar and more reduced than SRHA.The u nhydrated part of each rice husk ash is beneficial to the damping of cement mortar.The interface friction between the unhydrated part of each rice hull ash and the cement matrix may be an important reason for the damping improvement of cement mortar.