Mechanical and physicochemical performances of reinforced unfired clay bricks with recycled Typha-fibers waste as a construction material additive

Abstract

The aim of this study is to evaluate the suitability of recycled Typha-fibers waste as a construction material additive to unfired clay bricks. The novel approach of this paper is providing an alternative of damping Typha plants in landfills and waterways, by recycling these waste and putting them into good use as a construction material additive. Physicochemical and performance of prepared brick samples of clay plus recycled Typha-fibers waste additives, at multiple proportions (0%, 1%, 3%, 7%, 15% and 20%) by weight, are investigated according to the Moroccan testing standards in the building sector. A steady-state mixing technique with an electric stirrer, for 10 ​min and at 95 ​rpm, was adopted to ensure a homogenous distribution of the fibrous particles inside the clay matrix to produce homogenous mixtures. The used clay was found of type Illite with non-swelling characteristics and a dominant SiO2 content, 59.6%, following X-ray diffraction and fluorescence tests. The incorporation of high Typha-fibers’ waste additives produced more porous bricks; as 20% of additive content reflected the highest recorded porosity, of 14.95%, compared to reference samples, 1.14%. This prompted higher capillary water absorption coefficient with higher Typha-fibers waste proportions. A 55% increase in water absorption was observed with the incorporation of 20% additive content compared to reference samples; yet obtained capillary measurements were under the maximum permissible water absorption limit, according to Moroccan testing standards NM EN 772-11. In addition, bulk density measurements showed that prepared brick samples can be classified as lightweight structures, as their bulk density is lower than 1.75 ​g/cm3. Produced specimens were classified as Earth Blocks Class 4 (EB4), Earth Blocks Class 3 (EB3) and Earth Blocks Class 2 (EB2) according to their recorded compressive strength. It can be deduced that higher Typha-fiber additive content produced good functioning brick samples, following Moroccan and international testing standards, with a more porous and lightweight structures, higher water absorption ration and decreased compressive strength.