Using alginate biopolymer to enhance the mechanical properties of earth-based materials

Abstract

Natural materials such as sugars or biopolymers are commonly used to stabilize and enhance the mechanical properties of earth-based building materials. Among them, brown seaweed polymers such as alginate have been recently used to improve the design of earth building materials. With its molecular structure, alginate can form a strong network with clay particles that strengthens the material. We here focus on the mix-design of earth based materials using a model earth-based material based on a mix of sand and kaolinite and a real raw earth material. We have worked on castable earth-based material. The fluidity of the castable earth has been reached by using s dispersant (hewapetaphosphate) to reduce the apparent yield stress of the material. The gelification of the alginate has been advantageously used to shorten the demoulding time. The effect of alginate on the compressive strength has been shown to depend on its dosage ad on the mineralogy of the soil. If alginate increases the strength of kaolinitebased samples, it does not influence the behavior of earth-based materials with swelling particles. We finally study the possibility to reinforce earth-based materials containing alginate with flax fibers.