The cement industry¿s strategy in many countries is to reduce its CO2 emissions to diminish the greenhouse effect. This strategy aims to reduce these emissions by decreasing the clinker content in their new formulations, replacing it with supplementary cementitious materials (SCMs) or inert fillers. One of the most-used additions in Latin America¿s cement industry is inert limestone fillers, which is the most inexpensive one. In North America, there are restrictions on using this inert addition in portland cement, with a maximum allowable content of 15% as limestone content (LSC). Nevertheless, in Latin America and other countries, this limestone filler content restriction is not as strict, allowing contents of up to 35%. This investigation includes experimental results obtained from portland cement mortars where inert limestone fillers were used at a replacement level between 20 and 30% by clinker, and only 24-hour curing was considered. Results obtained include mechanical (compressive strength), physical (electrical resistivity, total void content, and capillary porosity), and chemical (carbonation after 1 year of natural exposure) performance of such mortars. The carbonation coefficients (kCO2) obtained after 1 year of exposure in a natural urban environment were 17.3, 22.9, and 24.5 mm/y1/2 for 23%, 27%, and 29% LSCs, respectively. These results were higher than typical kCO2 values of approximately 4 mm/y1/2 obtained from ordinary portland cement (OPC)-based mortars with a 90 to 95% clinker content, and standard 28-day water curing.
