Eco-friendly gypsum-lime mortar with the incorporation of recycled waste brick

Abstract

To reduce the consumption of cement and thus mitigate the negative impact of its manufacturing industry on the environment, the use of traditional gypsum and lime binders, with less environmental impact, was adopted in this work for the preparation of an eco-friendly mortar. Furthermore, recycled waste brick was incorporated as a replacement for sand to promote the recycling of construction and demolition waste on one side, and to reduce the depletion of natural sand resources on the other side.In this paper, the effect of the amount of lime, gypsum, and brick powder on the mortar properties was investigated. To this end, eight mortars were prepared using gypsum, lime, and gypsum-lime binders with and without brick powder. The replacement percentage of sand by brick powder in the gypsum-lime mortars was 33% and 66%. A cement mortar was also included for comparison purposes. It was observed that increasing the percentage of gypsum in gypsum-lime mortars improves bond, flexural, and dry compressive strengths but results in more porous structure and less resistance in the saturated state. Although the replacement of 66% of sand by the brick powder in mortars containing 66% of gypsum as binder increased the capillary absorption rate, it provided less dense mortars with a much better bond strength than cement mortar. It also improved the mechanical strength and especially the saturated strength compared to the mortar without brick powder addition. This improvement can be attributed to the formation of new CASH/CSH phases. The mortar containing 66% of gypsum as binder and 66% of brick powder as aggregate can be a very promising alternative towards an ecological mortar with less impact on the environment.