Effect of Accelerated Carbonation Curing On Properties of Pervious Concrete: An Effective Way of CO2 Sequestration and Water Conservation

Abstract

Climate change and global warming are the critical problems which today’s world is facing, and carbon dioxide is a major cause of these problems. Therefore, sustainable future needs a reduction in CO2 emissions as well as capture, storage, and consumption of already existing CO2 to reduce its adverse effects on the environment. One of the possible ways of reducing CO2 is through sequestration by accelerated carbonation curing (ACC). Accelerated carbonation curing is a technique in which CO2 is sequestrated by cementitious compounds. This sequestrated CO2 reacts with initial hydration products and results in the formation of calcium carbonate as one of the end products. Calcium carbonate has better mechanical properties as compared conventional hydration products and hence enhances properties of pervious concrete. Cementitious compounds are known for their ability to react with atmospheric CO2. ACC was used as curing technique for pervious concrete in the present study. For comparison, steam curing at 60°C and water curing regimes were also adopted. Further, in order to study the effect the duration of carbonation curing, ACC was adopted at two different carbonation duration; 6 hours and 12 hours. Further, in order to investigate the effect of different curing regimes on the microstructure of pervious concrete, SEM, XRD and TGA were conducted. The developed pervious concrete was then used to create interlocking paver blocks, and these blocks were tested for compressive strength and porosity. ACC for 12 hours has shown the highest 7 and 28-day compressive strength, and lowest permeability and porosity among all curing regimes. This was credited to the formation of calcium carbonate during ACC, and CSH on subsequent water curing of ACC specimen. Steam cured specimens showed high porosity and permeability due to the non-homogenous distribution of hydration products and introduction of micro-cracks at elevated temperatures.