TY - JOUR
T1 - Enhancement of recycled aggregates and concrete by combined treatment of spraying Ca2+ rich wastewater and flow-through carbonation
AU - Fang, Xiaoliang
AU - Zhan, Baojian
AU - Poon, Chi Sun
N1 - Funding Information:
This work was supported by the Research Grants Council GRF (PolyU 152144/17E), and The Hong Kong Polytechnic University.
Publisher Copyright:
© 2021 Elsevier Ltd
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/29
Y1 - 2021/3/29
N2 - Accelerated carbonation, regarded as one of the sustainable and economical methods for enhancing recycled concrete aggregates (RCAs), has a potential to be further enhanced through pretreating the RCA with Ca2+ rich solutions before carbonation as the externally provided Ca2+ was expected to yield more precipitation of calcium carbonate in the pores. This study utilized wastewater sourced from a ready-mix concrete plant combined with a flow-through carbonation method in order to enhance the quality of RCA as well as recycled aggregate concrete (RAC). The density and water absorption of (i) natural aggregate (NA), (ii) RCA, (iii) carbonated RCA (C-RCA), and (iv) wastewater pretreated and carbonated RCA (WW-C-RCA) were compared. The density, water absorption, sorptivity, compressive strength, chloride penetration of the concrete prepared with these four types of aggregate were analyzed and compared. The results showed that (1) pretreating RCA by the Ca2+ rich wastewater could further enhance the effects of the flow-through carbonation for RCA; (2) the improvement in RCA quality resulted in a better RAC performance; and (3) the microscopic analysis revealed the enhancement of RCA was attributed to a reduced porosity and an increased microhardness value of the adhered mortar of WW-C-RCA. This study demonstrated a feasible approach to combine three waste resources (RCA, wastewater, and waste CO2) to produce green concrete.
AB - Accelerated carbonation, regarded as one of the sustainable and economical methods for enhancing recycled concrete aggregates (RCAs), has a potential to be further enhanced through pretreating the RCA with Ca2+ rich solutions before carbonation as the externally provided Ca2+ was expected to yield more precipitation of calcium carbonate in the pores. This study utilized wastewater sourced from a ready-mix concrete plant combined with a flow-through carbonation method in order to enhance the quality of RCA as well as recycled aggregate concrete (RAC). The density and water absorption of (i) natural aggregate (NA), (ii) RCA, (iii) carbonated RCA (C-RCA), and (iv) wastewater pretreated and carbonated RCA (WW-C-RCA) were compared. The density, water absorption, sorptivity, compressive strength, chloride penetration of the concrete prepared with these four types of aggregate were analyzed and compared. The results showed that (1) pretreating RCA by the Ca2+ rich wastewater could further enhance the effects of the flow-through carbonation for RCA; (2) the improvement in RCA quality resulted in a better RAC performance; and (3) the microscopic analysis revealed the enhancement of RCA was attributed to a reduced porosity and an increased microhardness value of the adhered mortar of WW-C-RCA. This study demonstrated a feasible approach to combine three waste resources (RCA, wastewater, and waste CO2) to produce green concrete.
KW - Enhanced carbonation
KW - Pretreatment
KW - Recycled concrete aggregate
KW - Wastewater
UR - http://www.scopus.com/inward/record.url?scp=85099778298&partnerID=8YFLogxK
U2 - 10.1016/j.conbuildmat.2020.122202
DO - 10.1016/j.conbuildmat.2020.122202
M3 - Journal article
AN - SCOPUS:85099778298
SN - 0950-0618
VL - 277
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 122202
ER -