CO₂ Capture in Permeable Concrete Blocks through Carbonation in Various Environmental Conditions

Abstract This study aims to evaluate the behavior of CO₂ absorption through carbonation in permeable concrete blocks (CPER). The cementitious material was produced with varying grain size distributions of river gravel and set at two water-cement (w/c) ratios. Performance parameters established by the Brazilian Standard (ABNT NBR 16416/2015) were assessed by conducting flexural tensile strength and permeability coefficient tests. CO₂ uptake was measured by exposing permeable blocks to three different environmental conditions, using phenolphthalein as a chemical indicator to signal carbonation. The analysis considered two curing ages with immersion and carbonation depth verification in permeable blocks. The results indicate compliance with the standards and confirm the suitability of permeable blocks for CO₂ capture.