Effect of carbon sequestration methods on uptake potential and characteristics of ordinary portland cement-based concrete

Abstract

Cementitious concrete is considered potentially the largest avenue to utilize the captured carbon dioxide (CO2). Its capacity is significantly influenced by various parameters, including the CO2 introduction method for sequestration. This paper attempted to study the variation in carbon sequestration potential of ordinary Portland cement (OPC) based concrete and paste when the CO2 is introduced to the samples during mixing, curing and both. The carbonated samples obtained using the abovementioned methods have been compared in terms of CO2 uptake capacity, microstructural densification, porosity reduction, and strength variations. A maximum CO2 Uptake Capacity of about 25% was achieved under Standard Ambient Temperature and Pressure (SATP) conditions, with a maximum CO2 Conversion of 70.35% and 93.80% obtained at the surface for CO2 Mixing and CO2 Curing, respectively. Further, carbon-sequestered concrete (CSC) resulted in enhanced compressive strength, and reduced the size of pores in addition to making them uniform in size.