Interaction of a viscous biopolymer from cactus extract with cement paste to produce sustainable concrete

The development of sustainable building materials is essential in view of meting worldwide requirements of the green and sustainable economy; this aspect is crucial in cement concrete, in which commercial demand is increasing day by day. Superior quality concretes can be produced by using natural additives, such as biopolymers, being them harmfully respect to the environment. In this investigation, bio-additives prepared from cactus extract with varying concentrations was mixed into cement concrete mixtures for the manufacturing of sustainable concretes. The modified concretes were evaluated for their fresh and hardened state properties. The interaction of cactus extract with cement particles during hydration reactions was also examined by Fourier Transform Infrared Spectroscopy (FT-IR); the microstructural properties of the modified cement concrete was also studied through X-ray Diffraction (XRD) and Thermo Gravimetric Analysis (TGA). As a result, FT-IR evidenced that the additives containing polysaccharides enhanced the water retention of the concrete, preventing the early drying of the concrete mix and thereby reducing shrinkage cracks. Cactus extract enhances the viscosity property of the concrete mix and thereby improves the workability of the concrete mix. The results of the investigation also evidenced that modified concretes exhibit enhanced mechanical properties and durability characteristics. In particular, polysaccharides influence the strength characteristics of the additive modified concrete while proteins and fats have an impact on the workability and durability of modified concrete. Hence, the tested bio-additive could be considered as an eco-friendly, cheaper natural additive that could develop sustainable cement composites with upgraded workability, mechanical and durability characteristics.