Use of a plant based polymeric material as a low cost chemical admixture in cement mortar and concrete preparations

Aqueous extract of okra called here as bio-admixture was characterized and tested for using as a sustainable chemical admixture in the production of cement mortar and concrete. Several fresh and hardened states properties of cement mortars and concrete with and without the presence of bio-admixture were evaluated. Interactions of bio-admixture with cement particles during hydrations were also investigated by using conductometric and FTIR spectroscopic methods. Moreover, an improved method was developed to determine water retention capacity of cement pastes. Results indicate that the investigated bio-admixture exhibits viscosity enhancing property. In comparison to the reference cement paste, bio-admixture containing cement pastes have shorter setting times due to increasing hydration rate of cement particles. Solution chemistry and FTIR spectroscopic investigation indicate that the addition of bio-admixture enhances cement hydration rate. Increase hydration rate can be related with the interactions of pectin type heteropolysaccharides present in bio-admixture with Ca2+ ions of cement paste. Compressive strengths of bio-admixture containing mortar and concrete are higher than that of the reference specimens at the investigated curing period. Deterioration of strength of bio-admixture based mortars cured in MgSO4-NaCl solution is distinctly less in comparison to reference, depicting higher durability under such conditions. Most of the properties of cement mortar and concrete are also dependent on the concentrations of bio-admixture in aqueous solution. Therefore, investigated bio-admixture can be considered as a low-cost, environmentally benign viscosity enhancing admixture for producing sustainable cement composites having improved mechanical and durability properties.