Inhibiting effect of styrene-butadiene copolymer on the whitening of calcium aluminate cement mortar

•The white deposits were newly formed carbonized products C4AC¯H11 and CaCO3.•SB had a good inhibiting effect on the early and long-term whitening of CAC mortar.•C4AC¯H11 was no longer generated resulting in no visible whitening with 12% SB addition.•Capillary water absorption was closely related to the whitening of CAC mortar.•SB affects cement hydration, hydrophobicity and capillary water adsorption of CAC mortar.