Utilization of welan gum in enhancing workability, compressive strength and durability of self‐compacting concrete: Experimental investigation and air‐void structure analysis

Abstract This study investigates the effect of welan gum (WG) on the workability of self‐compacting concrete (SCC) and further evaluates its improvements in compressive strength, durability, and air‐void structure. A series of tests were conducted on fresh cement pastes and SCCs with five WG dosages ranging from 0.01% to 0.1% (weight percentage with respect to binder mass), allowing for their flowability and stability. Using the suggested WG dosages, durability tests containing freeze–thaw (FT) cycle, concrete carbonation, and chloride permeability were carried out to seek a satisfactory WG content for SCC. The results show the cement pastes with both water‐reducing agent (WRA) and WG exhibited a large spread diameter of 226–242 mm and a low bleeding rate from 2.13% to 2.56% at WG contents of 0.025%–0.05%. Similarly, under the same WG dosages, SCCs exhibited a high slump‐flow of nearly 630 mm and a sound segregation rate varying from 3.51% to 6.35%. The compressive strength of SCCs increased by 5.29% at 0.05% WG. All durability tests approved that the SCC with 0.025% WG exhibited superior resistances. The three‐dimensional polymer–cement network and uniformly distributed air‐void system could account for the enhancement due to WG in workability, compressive strength, and durability of SCC. All above findings could offer reliable advice on preparing SCC with superior comprehensive performance using a WG dosage of approximately 0.025% by binder mass.