TY - JOUR
T1 - Effect of carbonation duration on properties of recycled aggregate concrete
AU - Li, Long
AU - Ziyabek, Nazym
AU - Jiang, Yi
AU - Xiao, Jianzhuang
AU - Poon, Chi Sun
N1 - Publisher Copyright:
© 2023 The Authors
PY - 2023/12
Y1 - 2023/12
N2 - The use of recycled coarse aggregate (RCA) produced from waste concrete in new concrete is an effective way to realize the recycling of construction and demolition waste. The utilization of accelerated carbonation to enhance RCA has attracted a lot attention because it can enhance performance of recycled aggregate concrete (RAC) and has potential for CO2 sequestration. This study systematically investigated the influences of the duration of pressurized carbonation on the properties of RCA, RCA-new mortar interface, and RAC. The results showed that water absorption of carbonated RCA (CRCA) decreased with the increase of carbonation duration. But the beneficial effect of carbonation was less obvious after 1-day carbonation because most of calcium hydroxide and Ca-rich calcium silicate hydrates in RCA had reacted with CO2 within 1 day. After using CRCA, the improvement in different performance indicators of RAC was dependent on different factors. The enhancement in compressive strength and chloride penetration resistance of RAC prepared with CRCA were dependent on the reduced porosity of CRCA. That was why they correlated with the water absorption of CRCA as carbonation duration increased. However, the decrease in initial absorption of water of RAC was mainly dependent on the denser surface layer of CRCA, rather than the reduced porosity of CRCA. This is because the denser surface layer can change water path from “penetrating through RCA” to “passing around RCA”. It is recommended to use 1-day carbonation to enhance RCA, which might have higher cost-effectiveness.
AB - The use of recycled coarse aggregate (RCA) produced from waste concrete in new concrete is an effective way to realize the recycling of construction and demolition waste. The utilization of accelerated carbonation to enhance RCA has attracted a lot attention because it can enhance performance of recycled aggregate concrete (RAC) and has potential for CO2 sequestration. This study systematically investigated the influences of the duration of pressurized carbonation on the properties of RCA, RCA-new mortar interface, and RAC. The results showed that water absorption of carbonated RCA (CRCA) decreased with the increase of carbonation duration. But the beneficial effect of carbonation was less obvious after 1-day carbonation because most of calcium hydroxide and Ca-rich calcium silicate hydrates in RCA had reacted with CO2 within 1 day. After using CRCA, the improvement in different performance indicators of RAC was dependent on different factors. The enhancement in compressive strength and chloride penetration resistance of RAC prepared with CRCA were dependent on the reduced porosity of CRCA. That was why they correlated with the water absorption of CRCA as carbonation duration increased. However, the decrease in initial absorption of water of RAC was mainly dependent on the denser surface layer of CRCA, rather than the reduced porosity of CRCA. This is because the denser surface layer can change water path from “penetrating through RCA” to “passing around RCA”. It is recommended to use 1-day carbonation to enhance RCA, which might have higher cost-effectiveness.
KW - Carbonation duration
KW - Durability
KW - Interface
KW - Mechanical properties
KW - Recycled aggregate concrete
UR - http://www.scopus.com/inward/record.url?scp=85176264487&partnerID=8YFLogxK
U2 - 10.1016/j.cscm.2023.e02640
DO - 10.1016/j.cscm.2023.e02640
M3 - Journal article
AN - SCOPUS:85176264487
SN - 2214-5095
VL - 19
JO - Case Studies in Construction Materials
JF - Case Studies in Construction Materials
M1 - e02640
ER -