Durability of Cement Systems Reinforced with Wollastonite Microfibers

The performance of wollastonite reinforced portland cement based binders hydrated in saturated solution, distilled water, and saturated moist air was evaluated as a precursor to the development of a test for assessing the durability of these composites. The cementitious binders were made of cement and silica fume. The effect of the different solutions on the mechanical behavior and microstructural characteristics of the systems investigated at 24 deg C and 80 deg C was determined. Porosity and pore structure determinations were made using mercury intrusion porosimetry, helium pycnometry, and isopropyl alcohol saturation techniques. Flexural strength and fracture toughness behavior was also determined. Pore structure modifications, leaching effects and mechanical test results were discussed in the context of potential accelerated test criteria for the long-term stability of wollastonite micro-fibers in cement binders.