Recycled aggregate concrete, as a construction material, can be applied to structural components (beams, slabs, columns, and foundations), auxiliary components, and temporary facilities with strength grades ranging from C30 to C50. Today, the world is facing an increasing pressure of greenhouse gas emissions. Utilizing carbon dioxide for the curing of recycled aggregates contributes to achieving carbon reduction goals. Freeze damage can cause deterioration of mechanical properties and surface spalling of recycled aggregate concrete (RAC). This study investigated the influence of three different CO2 curing methods, standard CO2 curing (CC group), CO2 curing with pre-saturated Ca(OH)2 immersion (HH group), and whole specimen CO2 curing (CRR group), on the properties of RAC subjected to freeze-thaw cycles. The results revealed that all the three CO2 curing methods improved the peak stress and elastic modulus of RAC by 12.3%-13.7% and 19.2%-31.5%, respectively. The HH group suffered the least mass loss rate and experienced the most improvement in the relative dynamic modulus. The improvement in the RAC impermeability was in the descending order of HH group > CC group > CRR group. It should be pointed out that RAC with a lower initial water-cement (w/c) ratio exhibited better permeability resistance. Compared with the reference group, the CC, HH, and CRR groups showed a respective 49.0%-58.7%, 55.8%-72.6%, and 45.5%-46.8% reduction in the capillary water absorption coefficients after being subjected to different CO2 curing methods. Among the three groups, the HH group with a w/c ratio of 0.35 and 0.55 showed better resistance to chloride ion penetration (which was further reduced by 9.4%-31.6% and 19.2%-41.1%, respectively).

Spall

Frost (temperature)

Impact resistance

10.1016/j.cscm.2024.e02973

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Citations (7)

Recycling Bayer and sintering red muds in brick production: a review

Journal of Zhejiang University. Science A (2022)

Yujia Xiao Michelle Tiong Kim Hung Mo Ming-Zhi Guo Tung‐Chai Ling

Brick

Efflorescence

Red Mud

Cementitious

Prima materia

10.1631/jzus.a2100476

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Citations (9)

Synthesis of High Belite Sulfoaluminate Cement with High Volume of Mixed Solid Wastes

SSRN Electronic Journal (2022)

Xiao Li Wang Ming-Zhi Guo Gongbing Yue Tung‐Chai Ling

The objective of this study was to synthesize high belite sulfoaluminate cement at low sintering temperatures with petroleum coke desulfuration residue, fly ash, carbide slag, and bauxite. The thermal behavior, mechanical properties, heat of hydration, hydration products of the cement were investigated. The results showed that C4A3S , β-C2S, and C4AF were produced at 1225~1300°C, and the industrial wastes can use up to 80%. The optimal sintering condition was 1300°C, 45 min, and 10 °C/min, and the corresponding 1-d and 28-d strengths were 27.7 and 51.4 MPa. The early hydration products were composed of AFt, AH3, unhydrated C4A3S, C2S, CaSO4, and trace CH. The network structure formed by AFt interweaving was filled with AH3, which was conducive to the improvement of strength. Furthermore, the cumulative heat release of the developed cement (191J/g) in 3d was lower than that of SAC (198J/g), effectively alleviating the rapid setting problems.

Belite

10.2139/ssrn.4011011

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Citations (1)

Influence of ultrasonic triggering parameters on recovery performance of microcapsule-mediated self-healing cement mortar

Journal of Building Engineering (2022)

Zijian Song Na Xu Lin Yu Ming-Zhi Guo

Power density

10.1016/j.jobe.2022.105413

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Citations (2)

Effects of early hydration of alite and belite phases on subsequent accelerated carbonation