Elaboration et caractérisation d’un mortier avec un additif naturel

Abstract

The economic challenges linked to the rising costs of fossil resources, their scarcity, and the environmental impacts related to their production and use are pushing construction stakeholders toward natural materials. Biomass-derived resources are now at the forefront, including kaolin (chamotte). The addition of chamotte to mortar aims not only to reduce the environmental impact of cement but also to improve certain material properties, such as dimensional stability, water resistance, and long-term durability. The objective of our study is to enhance quarry sand by blending it with chamotte sand. The main goal is to monitor the effect of different chamotte percentages on mortar behavior. In this research, concrete sand was replaced by chamotte sand at 5%, 10%, 20%, and 30%, respectively. The properties of the valorized aggregates, along with the physical and mechanical analysis of both fresh (workability) and hardened mortars (shrinkage, capillarity, swelling, compressive strength, and flexural tensile strength), were analyzed and compared to the reference mortar (100% natural aggregates) at 3, 7, and 28 days of curing. The results clearly showed that the progressive inclusion of chamotte in the mortar mix significantly improved certain physical properties of the mortar, such as reduced shrinkage, swelling, and water absorption, although it led to a decrease in mechanical strength. Therefore, mortar with chamotte incorporation is considered a refractory mortar, ideal for applications requiring high heat resistance, such as kilns, chimneys, or fireplaces. Chamotte, a calcined and ground clay, is added to mortar to enhance its thermal resistance and durability at high temperatures.