EFFECTS OF CO2 PENETRATION ON THE PROPERTIES OF SELF-COMPACTING MORTARS WITH HIGH CONTENTS OF SUPPLEMENTARY CEMENTITIOUS MATERIALS

• DOI: https://doi.org/10.22533/at.ed.2642418074

• Palavras-chave: -

• Keywords: Cleaner production. Resistance to CO 2 penetration. Sustainability. Mineral admixtures.

• Abstract: This article evaluates the influence of accelerated carbonation on mortars with reduced amounts of cement intended for self-compacting concrete (SCC). To this end, cement was replaced by different types of supplementary cementitious materials (SCMs), including metakaolin (MK), rice husk ash (RHA) and sugar cane biomass ash (SCBA). In addition, hydrated lime (HL) was added to some mixtures to replenish the alkaline content of the system. The effects of the carbonation of the pastes with SCMs and with the addition of HL were observed using X-ray diffraction (XRD), thermogravimetry (TG) analyses and compressive strength tests. HL optimized the alkaline reserve together with MK, but did not interact well with SBCA, increasing the depth of carbonation. However, the pastes with the SCMs showed carbonation depths below the normative standards. The XRD results revealed preferential carbonation of calcium hydroxide compared to secondary C-S-H. In terms of compressive strength, the pastes with SCMs and with and without the addition of HL obtained lower results, which, however, does not make the use of these materials unfeasible since the loss of strength was not significant. The results show that the use of high contents of SCMs and the addition of HL are important to obtain self-compacting pastes that are more resistant to CO 2 penetration, which will help to obtain more durable constructions with a lower carbon footprint.