Using biopolymers as anti-washout admixtures under water concreting

In this study, we investigate the use of natural additives (biopolymers) resistant to scouring. To this end, three natural substances, Kathira, sodium alginate, and guar gum, have been utilized as additives resistant to scouring, and we examine their mechanical performance, resistance to scouring, and the properties of fresh concrete including slump test, setting time, and ultimately shrinkage test. For this purpose, a total of 12 cylindrical specimens with dimensions of 15 by 30 cm were prepared for 28-day compressive strength test, and 12 cylindrical specimens with dimensions of 15 by 30 cm were prepared for 28-day indirect tensile strength test. Additionally, 12 concrete beams with dimensions of 10 by 10 by 35 cm were fabricated for a 28-day flexural strength test. All laboratory specimens were submerged in lime-saturated water for hydration for a period of 28 days for maintenance and preservation. The results indicate that all three biopolymers improve resistance to scouring, and, two substances enhance compressive, tensile, and flexural strength. Furthermore, all of them lead to a reduction in concrete shrinkage.