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This study investigates the effect of vibration duration on the porosity, permeability, and compressive strength of pervious concrete incorporating 50% recycled concrete aggregate. Mixtures were prepared with Portland cement (CEM I) and blended cement (CEM II), and compacted by tamping or table vibration for durations ranging from 10 to 60 s. A refined falling-head permeability test was developed, using a novel circumferential heat-shrink sealing to eliminate lateral flow and ensure axial water penetration. Pore structure and connectivity were characterized using optical microscopy and X-ray micro-computed tomography. Increasing vibration duration reduced porosity and permeability while enhancing compressive strength. An optimal compaction window of approximately 30 s, corresponding to a normalized vibration dose of 226, provided the best balance between hydraulic and structural performance. Micro-computed tomography confirmed a highly interconnected pore network and strong agreement with effective porosity, demonstrating the value of three-dimensional metrics in mix design. The results show that combining recycled aggregate with low-carbon blended cements can meet functional performance targets while reducing cradle-to-gate carbon dioxide emissions by up to 25%. These findings offer practical guidance on compaction regimes and testing protocols, supporting reproducible and sustainable applications of pervious concrete in pavement infrastructure.

The global cement industry faces a critical challenge of reducing its substantial carbon footprint while maintaining material performance. Portland cement production significantly contributes to global CO2 emissions, necessitating innovative sustainable alternatives. This study evaluates the transformative potential of calcined natural pozzolans as a strategic approach to developing low-carbon cement. By systematically investigating the effects of calcined natural pozzolans derived from kaolinite and pyroclastic rocks on cement paste properties, the research demonstrates a promising pathway to environmentally efficient cement formulations. Utilizing advanced characterization techniques including XRD, TGA, SEM-EDX, and gas adsorption porosimetry, this study provides insights into hydration kinetics, compressive strength development, microstructural evolution, and porosity refinement. The results reveal that calcined natural pozzolans strategically enhance cement performance by accelerating hydration processes, improving compressive strength, and sophisticating microstructural characteristics. Notably, pastes incorporating pyroclastic rock pozzolans exhibited superior mechanical properties, with 28-day compressive strengths exceeding ordinary Portland cement by 35.2%. These findings not only validate the technical feasibility of natural pozzolan-based low-carbon cement but also underscore their potential to meaningfully reduce the construction industry’s environmental impact.

Low-heat expansive cement (LHEC) is an environmentally friendly and low-carbon cementitious material. Compared to ordinary Portland cement (OPC), LHEC reduces CO2 emissions from the cement production process; furthermore, it enhances the service life of the cement by overcoming the problem of OPC’s strength inversion in hot and humid environments. In order to improve the performance of LHEC in a hygrothermal environment, the strength and expansion of LHEC with different gypsum dosages (8–20%) at curing temperatures of 20 °C, 50 °C, and 80 °C were investigated. The corresponding mechanism was investigated using XRD, TGA, SEM, and porosity analyses. The results indicate that there is a ‘critical gypsum dosage’ for strength at 20 °C. The ‘critical dosage’ rises with the curing temperature or an increase in age. Raising the curing temperature has a better effect on the strength of cement with a higher gypsum dosage; it does not have such a positive effect on cement with a low gypsum dosage. The higher the gypsum content, the greater the expansion rate, and the longer the time needed for the expansion to stabilize. The higher the curing temperature, the shorter the time required for stable expansion and the lower the final expansion rate. Increasing the gypsum dosage and maintaining the temperature promote the hydration of slag and the formation of ettringite (AFt), thereby enhancing the microstructure of the cement. AFt decomposition occurs in the case of a low gypsum dosage and high curing temperature. According to the above results, it is inferred that the strength and expansion performance of LHEC in a hygrothermal environment can be improved by appropriately increasing its gypsum dosage. This finding offers valuable insights for the improvement of LHEC and its application in hygrothermal conditions.

Vietnam is the world’s largest cement exporter. In 2022, it produced 118 Mtpa cement while emitting 109 Mtpa cement-related CO2, equal to 33% of Vietnam’s total CO2 emission. As Vietnam has pledged to achieve net zero by 2050, unabated cement-related CO2 emission must be drastically reduced in the future. This paper investigates the contribution of carbon capture and storage (CCS) to decarbonizing Vietnam’s cement industry to make cement production cleaner and more sustainable. A first-of-a-kind CO2 source-sink mapping exercise was conducted to map 68 cement plants to subsurface sinks, including oil and gas reservoirs and saline aquifers, using four CCS field development concepts. The results have identified four first-mover CCS projects where CO2 emissions from 27 cement plants are mapped to nearby offshore subsurface CO2 sinks. Two of these projects are located in Vietnam-north, one in Vietnam-central, and one in Vietnam-south. In the Vietnam-south CCS project, CO2 emission from the Kien Giang province is transported and stored in the offshore Block B gas field. In the other three CCS projects, CO2 emission is transported to nearshore saline aquifers in the Song Hong Basin. At a CO2 capture rate of 90%, these four projects will mitigate 50 Mtpa CO2, which is 46% of cement-related CO2 emission or 15% of total CO2 emission from Vietnam, thus making Vietnam’s cement production cleaner and more sustainable. Future research should focus on subsurface characterization of saline aquifers in the Song Hong Basin. The methodology developed in this study is usable in other cement-producing countries with significant CO2 sinks in the nearshore continental shelf.

The use of supplementary cementitious materials and the CO2 uptake capacity of cementitious materials—including recycled concrete aggregates—not only promotes the circular economy but may also present an opportunity to increase their ecoefficiency, thus improving the shrinkage and durability properties of concretes. This study analyses the impact of carbonated recycled aggregates and CO2 curing on improving the properties of commercial structural self-compacting concrete. Recycled aggregate concretes (RACs) were produced using 50% and 60% coarse recycled concrete aggregate (RCA), in carbonated and uncarbonated forms, and two types of cement—ordinary Portland cement (CEM I) and CEM II/B-M Portland composite cement containing 24% less clinker than CEM I—all with similar compressive strengths. After evaluating the CO2 curing process, the physical, mechanical, shrinkage, and durability properties (including suction and carbonation resistance) of the concretes were assessed. The properties of the RACs were compared with those achieved by conventional concrete, to generate insights for developing a highly sustainable concrete manufacturing process. Taking all the assessed properties into account, the CO2 curing process improved concrete’s properties. In addition, RAC-C50-I concrete (using CEM I with carbonated RCA) and RAC50-II (using CEM IIB and uncarbonated RCA) exhibited the greatest durability, resulting in reductions in sorptivity values of 40% and 45%, and decreases in the carbonation coefficient of 16% and 21%, respectively, compared to concrete without CO2 curing.

Limestone Calcined Clay Cement (LC3) Technology is a low carbon cement that combines limestone, calcined clay, and clinker, aiming to reduce CO2 emissions by 40%-50% during production. In this study, large-scale investigations were conducted to explore LC3 as a potential substitute for conventional cement (CC). Mechanical and durability tests were performed on LC3, comparing results with CC and Pozzolana Cement (PC) concretes. The findings revealed that LC3 concrete exhibited promising early-stage strength similar to CC concrete. However, at 90 days, LC3 showcased a 10% higher strength compared to CC concrete. Additionally, LC3 displayed a remarkable 45% increase in resistance to moisture ingress, indicating improved durability over CC concrete. These results highlight the efficacy of low carbon cement in developing ternary blended cements that offer early strength and enhanced durability, making it a viable eco-friendly alternative in the construction industry.

As an environmentally friendly cement material in green buildings, due to its low contribution to air pollution and its substantial use of solid waste, supersulfated cement (SSC) has been extensively studied. However, the low early strength of sustainably utilized SSC needs to be addressed. In order to use SSC to achieve great reductions in energy consumption during industrial production, the effects of triethanolamine (TEA), diethanolisopropanolamine (DEIPA) and triisopropanolamine (TIPA) (with dosages ranging from 0.02% to 0.08%) on the strength and hydration of SSC were studied, and the underlying mechanism was analyzed by TGA, XRD and SEM. The results show that TEA and DEIPA significantly improve the 3-day and 28-day strength of SSC. The former is better at low dosages, while the latter is more suitable for high dosages. TIPA also enhances the 3-day strength of SSC, but it is not as good as the other two alkanolamines. The chelation of alkanolamine with Al3+ ions plays an important role in the strength development of SSC, which accelerates the decomposition of slag and the formation of ettringite. In summary, adding alkanolamines to low-carbon cement systems with a high proportion of industrial by-products such as SSC is a potential and effective solution. In addition, alkanolamines can be used as a strength promoter for most low-carbon blends, which fully utilize solid waste.

The construction sector faces pressure to decarbonise while addressing rising resource demands and agricultural waste. Ordinary Portland cement (OPC) is a major CO2 emitter, yet biomass residues are often open-burned or landfilled. This study explores corncob ash (CCA) as a sustainable supplementary cementitious material (SCM), examining how calcination conditions influence pozzolanic potential and support circular economy and climate goals, which have not been adequately explored in literature. Ten CCA samples were produced via open-air burning (2–3.5 h) and electric-furnace calcination (400–1000 °C, 2 h), alongside a reference OPC. Mass yield, colour, XRD, XRF, LOI, and LOD were analysed within a process–structure–property–performance–sustainability framework. CCA produced in a 400–700 °C furnace window consistently achieved high amorphous contents (typically ≥80%) and combined pozzolanic oxides (SiO2 + Al2O3 + Fe2O3) above the 70% ASTM C618 threshold, with 700 °C for 2 h emerging as an optimal condition. At 1000 °C, extensive crystallisation reduced the expected reactivity despite high total silica. Extended open-air burning (3–3.5 h) yielded chemically acceptable but more variable ashes, with lower amorphous content and higher alkalis than furnace-processed CCA. Simple industrial ecology calculations indicate that valorising a fraction of global CC residues and deploying optimally processed CCA at only 20% OPC replacement could displace 180 million tonnes CC waste and clinker avoidance on the order of 5–6 Mt CO2 per year, while reducing uncontrolled residue burning and primary raw material extraction. The study provides an experimentally validated calcination window and quality indicators for producing reactive CCA, alongside a clear link from laboratory processing to clinker substitution, circular resource use, and alignment with SDGs 9, 12, and 13. The findings establish a materials science foundation for standardised CCA production protocols and future life cycle and performance evaluations of low-carbon CCA binders.

Limestone calcined clay cement (LC 3 ) is a novel and environmentally friendly cement that is a blend of OPC clinker, calcined clay, limestone, and gypsum. Concrete paving blocks for footpaths and roads are favorable because of their ease of installation and improved appearance with a smooth surface. The incorporation of LC 3 into paver blocks improves their quality while simultaneously being environmentally friendly. The present investigation deals with the analysis of different sizes of concrete pavement blocks of the M30 grade. This study aimed to investigate the effects of using LC 3 with sand and quartz aggregates at aspect ratios of 1.5, 2.43, and 3.25. The mechanical and durability properties studied include tensile strength, flexural strength, compressive strength, and abrasion resistance. The strength parameters including the compressive strength and flexural strength of the paver blocks were determined to vary between 32.0-39.61 MPa and 5.5-8.6 MPa respectively. The tensile strength was in the lower range of 1.5-2.1 MPa. It was concluded that as the aspect ratio (length-to-thickness ratio of the pavers) was reduced, the strength attributes decreased. Thus, the incorporation of LC 3 cement to develop paver blocks can be an environmentally friendly solution with a 40% reduction in CO 2 .

Downsizing fossil fuel dependence and greenhouse gas emissions is at the forefront of a sustainable future. The expansion of renewable energy while striving to minimize dependence on fossil fuels has led to biomass taking the lead among renewable energy sources, with wood having the broadest application. Along with the growing trend of using biomass as a renewable energy source, the combustion of wood biomass results in wood biomass ash (WBA), leading to compelling amounts of waste. In this study, the technical feasibility of fly WBA from different Croatian power plants was analyzed to evaluate its potential use in precast concrete drainage elements and curb units. By implementing a performance-based design, the influence of various factors in thermal processing of wood biomass was investigated, together with a detailed characterization of WBA in order to assess the feasibility of using WBA as a secondary raw material in a large-scale industrial batching plant. The compressive strength and durability properties (water absorption, permeability, and freeze–thaw resistance) of concrete mixtures with WBA as a replacement for 15 wt% cement were evaluated and compared with the precast concrete manufacturer’s technical requirements. The main concerns identified were compositional inconsistency of WBA, workability downturn, delay in initial reactivity rate, and increased water absorption. Concrete with WBA based on a circular design has been found to be a viable solution to cement depletion, stepping up from recycling to reuse of industrial waste.