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The cement manufacturing industry, a resource- and energy-intensive sector, took up more than 15% of total greenhouse gas emissions in China, thus finding a clean technology option for sustainable development is essential. CO 2 curing has emerged as a promising novel method for large-scale carbon sequestration and mechanical properties improvement of cement-based composites. Currently, a body of related works is mainly investigated in the laboratory, and understandings of the behaviors of CO 2 -cured cement-based composites are still less than complete, including, 1) the CO 2 storage potential has plenty of room for improvement due to the influence mechanism of variables factors remains unclear; 2) previous evaluations were mostly based on the subsets of individual result rather than an integrated dataset; 3) whether CO 2 curing is suitable for the manufacturing process of reinforced concrete. Therefore, this paper presents a comprehensive overview covering a wide range of parameters as well as fabrication, mechanical (compressive strength), and environmental (CO 2 uptake value) performances on the basis of a correct understanding of the differences between active and passive carbonation reactions. Notably, the influences of critical factors, including those less understood, e.g., types of curing setup (flow-able, enclosed, and others), components of binder, and aggregate/binder ratio, are also analyzed and the corresponding mechanisms discussed to achieve satisfied curing efficiency. Besides, corrosion-related challenges are also be pointed out to convince the widespread acceptance of this technology. Finally, based on this paper, limitations of existing research are identified and future scope on CO 2 curing regime is proposed. • 170 studies related to CO 2 /carbonation-cured cement-based composites are analyzed. • The differences between active/passive-carbonation together with reaction mechanisms are expounded. • Fabrication and influence factors on engineering and environmental properties are systematically reviewed. • CO 2 -cured cement-based composites exhibit excellent resistance to aggressive conditions. • The challenges and opportunities in the CO 2 curing method are innovatively discussed. [ABSTRACT FROM AUTHOR]

The disposal of waste coal gangue (WCG) is still a serious problem for areas that rely on the coal mine industry, especially in the northern part of China. This paper investigated the improving behavior and corresponding mechanism by waste coal gangue on the dispersivity, water stability and mechanical properties of dispersive soil. Dispersive soil samples with different contents of natural waste coal gangue, varying from 1% to 10%, were prepared and cured for 0, 1, 3, 7, 14 and 28 days. Dispersivity and water stability of soil samples were evaluated by pinhole test, cube sample crumb test and remoulded sphere sample crumb test. Electric conductivity and pH of soil samples were monitored during 28 days of curing. Unconfined compression test and splitting test were performed to determine the compressive and tensile strength of soil samples. Microstructural and mineral analysis methods such as SEM, EDS and XRD were conducted to determine the microstructural and mineral changes during curing time. Experiments show that waste coal gangue could restrain the dispersivity and enhance the water stability of dispersive soil, subsequently changing dispersive soil into nondispersive soil. Increases of 591% and 192% are observed when WCG content increases from 1% to 10% and curing time increases from 0 to 28 days for compressive and tensile strength, respectively. Increasing in waste coal gangue content and curing time would better promote the positive effect of waste coal gangue, on both the dispersivity modification and strength improvement of dispersive soil. Microstructural and mineral analyses show that newly generated products among soil particles increase the friction and cohesion between soil particles. Results indicate that reusing of waste coal gangue as an admixture in dispersive soil is a feasible way, which would solve the disposal of waste coal gangue and optimize the poor properties of dispersive soil at the same time. Enhancing water stability of dispersivity soil would ensure the safety and normal operation of soil structures. • Modification experiment of dispersive soil by waste coal gangue is studied. • Waste coal gangue is capable of changing dispersive soil into nondispersive soil. • Water stability of dispersive soil is enhanced by waste coal gangue. • Mechanical property of dispersive soil is improved by waste coal gangue. [ABSTRACT FROM AUTHOR]