Effect of activated coal waste and treated Pinus fibers on the physico-mechanical properties and durability of fibercement composites

The constant environmental and social pressure on the search for alternative and clean technologies has strongly influenced the construction industry, which is considered as one of the main contributors to global warming due to the emission of carbon dioxide (CO2). The objective of this study was to evaluate the effect of partial replacement of cement by activated coal waste on cement-based composites reinforced by unbleached pine pulps. The results showed that the hornification treatment reduces the water absorption capacity and increases the dimensional stability of the cellulosic pulp. In addition, the thermal treatment preserves the original chemical composition of the vegetable pulp. Moreover, the partial replacement of cement by activated coal waste (ACW) increased the mechanical performance. The results of thermogravimetric analysis showed that composites with ACW present a decrease of the calcium hydroxide content compared to composites containing limestone. After accelerated aging tests, a decrease in the reinforcement capacity of the fiber and densification of the material is observed. However, composites with treated pulps and activated coal waste showed higher mechanical prop-erties and a greater durability. According to the results, the combination of the hornification treatment and the partial replacement of cement by ACW can be used to improve the eco-efficiency of the fiber cement industry. The combination of both approaches allows to a reduction the carbon dioxide emissions (reduction of cement consumption) and an increase of the durability of the material.