Research On Sisal Fiber Cement Mortar Shrinkage Cracking

Wall crack phenomenon is widespread in the projecta,tpresent，the commonlyused method to improve this situation is incorporating fiber.sisal fiber is a kind ofideal mortar reinforced material，has many advantages,such as low prices,qualityof a material tenacity,high tensile strength， wear resistance,acid and alkaliresistance， water resistance, corrosion and good low temperatureresistance．Comprehensive research at home and abroad,the study of sisal fiber incement mortar has not yet found，the literature of sisal fiber is also rare.Inreference to a large number of literatures,this paper proposed using sisal fiber as anew type of mortar，tightly around the theme of mortar shrinkage cracking, fromthe mechanism of the cement base material，the increase in experimental studysuch as research and development of sisal fiber to improves performance of thecracking of cement mortar．This paper is through a lot of test to find out theoptimum content of sisal fibe，and quantitative analysis of shrinkage cracking ofmortar,hoping to find judge mortar cracking performance indicators．First in this paper，the cement mortar optimal mixture ratio test show that thewater cement ratio0.45，mortar than1:3，the performance of mortar is better；Testto determine the best mixing process of cement mortar by using dry mixing mortardispersion is best，namely，cement．Secondly this article put forward the concrete small hollow block as thesubstrate，combine with plate method to study the internal moisture migration andcracks of sisal fiber to cement mortar，and further analysis of moisture migrationwithin the cement mortar plastic shrinkage cracks in their relationship to thesubstrate binding plate method．Test showed that：(1) With the increase of fibercontent，mortar surface water evaporation decreases，and the evaporation rate ofwater evaporation rate also decreases；(2) not add fiber mortar crack，with theincrease of fiber content， the first crack in the mortar appeared time prolong,peaked at3%， after then the mortar almost no crack,plastic crackresistance mortar is best．Finally mortar dry shrinkage crack resistance test of the mortar free shrinkagerate of different age，analyses the fiber content on the influence of different instarsof dry shrinkage，test the shrinkage rate under the restricted condition at the sametime，the shrinkage of mortar specimens were calculated the fiber stress，analysesthe age，the influence of the fiber dosage on mortar shrinkage stress．Combinedwith the shrinkage cracking performance and mixing processexperiment,determine the best mix of sisal fiber is3%．In the final analysis tocalculate the age28days under different dosage of sisal fiber mortar elasticmodulus，and establishes the quantitative evaluation index of crack resistancemortar crack resistance．...