Effect of Addition of A Marble Dust on Drying Shrinkage Cracks of Cement Mortar Reinforced with Various Fibers

Abstract

This investigation is conducted to study the effect of addition of marble powder (marble dust) and different fibers on drying shrinkage cracks and some properties of fibers reinforcment cement mortar. Steel molds having a trapezoidal section, and the end restrained at square shape with( 2.7 meter) at length are used to study restrained drying shrinkage of cement mortar. Specimens of ( compressive .flextural. splitting strength) were cast. The admixture (marble dust) was used to replacie weight of cement with three levels of (4%, 8% and 16%) and the fiber hemp and sisal fiber were added for all mixes with proportion by volum of cement . All specimens were cured for (14 days). Average of three results was taken for any test of compressive, tensil and flextural strength. The experimental results showed that the adding of this admixture(marble dust) cause adelay in a formation of cracks predicted from a drying shrinkage ,decreases of its width , and hence increases of (compressive, splitting tensil and flextural strength) at levels of (4%, and 8%). Thus there is a the positive effect when fiberes added for all mixes of cement mortar with addition of (marble dust). All The admixtures (marble dust and fibers) have the obvious visible effect in the delay of the information of shrinkage cracks and the decrease of its width as Compared to the cement mortar mixes when marble dust added a alone.