PHstimuli‐responsive poly(acrylamide‐co‐sodium alginate) hydrogels prepared by γ‐radiation for improved compressive strength of concrete

Abstract

AbstractCross‐linking of superabsorbent hydrogels based on poly(acrylamide‐co‐sodium alginate) is carried out using60Co γ‐radiation. Hydrogels ofPAM/NaAlg with 1.5:0.5 and 1.0:1.0 w/v concentrations showed good gel contents of 87 and 66 (%) and swelling degrees in water of 3.7 and 5 (g/g) after 40 min, respectively. The chemical structure of the hydrogel is confirmed byFTIR,XRD, andESR. The morphology of the hydrogel is observed using scanning electron microscopy. Intramolecular H‐bonding in the hydrogel network is confirmed byTGAandDSC. ThepH‐responsive swelling behavior of (PAM‐co‐NaAlg) hydrogels is tested in differentpHranges showing higher swelling capacities in basic than in acidic media. This property proposes the use of (PAM‐co‐NaAlg) hydrogel as internal curing agent for concrete. The hydrogel is examined with cement weight ratios of (0.1–0.5) wt%. The study shows that cement with (PAM‐co‐NaAlg) hydrogel improves the compressive strength of cement at 0.1 and 0.2 wt%.