The Use of Wollastonite to Enhance the Mechanical Properties of Cementitious Composites

Abstract

Cement composites are designed for two main goals; strength and durability. Reinforcing concrete with steel or carbon microfibers nowadays became the first solution to enhance their resistance and durability. On the other hand these microfibers are considered to be expensive comparing to natural occurring mineral microfibers as Wollastonite. Wollastonite is commonly known worldwide and it has a major industrial importance. It is used primarily in ceramics, friction products, paint filler, and plastics. In the past years studies have been made to use Wollastonite in cementitious composites to enhance its strength and durability. In this study, the potential of using Wollastonite powder as a partial substitute of cement or sand to enhance the properties of Portland cement mortars was investigated. The experimental program included the following tests: time of setting test, compression test, flexure test, drying shrinkage test and scanning electron microscopy. Two groups of Portland cement mortar mixes were used in this research. The first group incorporated Wollastonite powder as partial substitute of cement with replacement levels of 10%, 20%, and 30% by weight. The second group incorporated Wollastonite powder as partial substitute of natural sand with replacement levels of 10%, 20%, and 30% by weight.