Effects of HEMC Powder and PP Fiber on the Drying Shrinkage of Cement Mortar

摘要

Influences of polypropylene (PP) fiber and hydroxyethyl methyl cellulose (M) on the shrinkage rate of cement mortar and its potential mechanism were investigated. Results show that both the addition of trilobal PP fiber and M would reduce the shrinkage rate of cement mortar if well applied. With the increasing of PP content, the shrinkage rate firstly decreases and then increases, and reaches the lowest shrinkage degree with fiber content of 0.20% (volume fraction). While for cement mortar with M, the greater the dosage, the less drying shrinkage rate. An addition of 0.6% M contributes to a decrease of 23.8% for the 180-days drying shrinkage than the control. Additionally, a combination of both PP fibers and M can significantly reduce the drying shrinkage of mortar, resulting in a decrease of 40% for the shrinkage rate.