High durable latex-modified-concretes: the effect of minimum film formation temperature of acrylic-styrene latex

چکیده مقاله

This paper aimed to investigate the effect of the minimum film formation temperature (MFFT) of acrylic-styrene latexes (ASL) on the durability, physical, and mechanical characteristics of latex-modified concretes (LMCs). LMCs were designed and manufactured incorporating three ASLs with different MFFTs, namely 0, 8, and 25 °C (Water/Cement mass ratio=0.445 and latex/water mass ratio=0.05). Water absorption (WA), rapid chloride ion migration, carbonation, compressive-splitting tensile strength, and scanning electron microscopy (SEM) were employed to study LMCs properties. The performance of LMCs was found to be dependent on the MFFT of the latexes strongly. The results revealed that LMCs containing ASL with lower MFFT compared to ambient temperature (MFFT<25 °C) had a lower slump, compressive and tensile strength, and higher WA, chloride ion, and CO₂ penetration due to the higher film formation rate of latexes on the non-hydrated cement particles and the decreased final hydration degree. Furthermore, it was indicated that chloride penetration, water adsorption, and tensile strength of LMCs containing latexes with high MFFT (MFFT>25 °C) decreased by 14 %, 10 and 20 % compared to the conventional concrete, respectively. Such a chloride penetration reduction is a great achievement. Accordingly, carboxylated alkaline ASLs with high MFFT can be a promising candidate for preparing the LMCs, which can be applied in reinforced concrete in corrosive conditions.