Title: Studies on Some Factors Affecting CO2 Mixing or CO2 Curing of Cement Concrete

Author(s): Ming-Gin Lee, Yung-Chih Wang, Yu-Min Su, and Yishuo Huang

Publication: Symposium Paper

Volume: 326

Issue:

Appears on pages(s): 120.1-120.8

Keywords: carbon dioxide, strength, concrete, CO2 mixing, CO2 curing

DOI: 10.14359/51711103

Date: 8/10/2018

Abstract:

It is a well-known fact that cement can react with carbon dioxide in the moisture environment. This paper deals with the effects of several factors, such as CO₂ pressure, CO₂ concentration, curing time, water- cement ratio and continued curing after CO₂ mixing or CO₂ curing of cement concrete in the above parameters. Finally, the compressive strength, CO₂ reaction, and carbonation degree of concretes were tested after the specific curing time. The performance of the CO₂ cured mortars was found through the measurement of pressure drop, temperature rise, strength development, mass gain, and carbonation. Results indicated that CO₂-mixed concrete could be more efficient to absorb carbon dioxide by using this pressure method. The results found that the mixing concrete react with carbon dioxide in a short time, and shorten the initial setting time of concrete. The phenolphthalein tests indicated that under most curing conditions the CO₂ penetrated through whole specimens, however, the reactions between CO₂ and cement matrix occurred mainly on the surface of cement particles. The results of CO₂-cured concrete show that the lower water-cement ratio or longer CO₂ curing time produced higher early strength. However, the concrete specimens mixed with CO₂ under 0.2~0.6 MPa pressure produced lower compressive strength.