The use of Wollastonite to enhance the mechanical properties of mortar mixes

The effect of using mineral Wollastonite powder as a partial substitute of cement or sand in Portland cement mortar mixes was studied. Seven different mixes of mortar incorporating Wollastonite as a partial substitute of cement or sand with replacement levels of 10%, 20%, and 30% were prepared and tested. Initial setting time was measured and a delay up to 60% was observed for mortar mixes with 30% sand replacement while mortar mixes with cement replacement showed a marginal increase up to 5%. Compression test results showed a 45% increase in compressive strength due to 20% sand replacement. Flexural strength was enhanced by 28% by the same batch. The effect of Wollastonite in resisting drying shrinkage was investigated and test results showed a reduction in length change for both mortar mixes with 30% cement replacement and 30% sand replacement up to 47% and 44% respectively.