Cleaner Materials最新文献_第9页

Mechanical properties, life-cycle assessment, and costs of alternative sustainable binders to stabilise recycled aggregates 机械性能，生命周期评估，和成本替代可持续粘合剂稳定再生骨料

Cleaner Materials

Pub Date : 2025-02-18 DOI: 10.1016/j.clema.2025.100302

Luca Tefa , Bartolomeo Coppola , Paola Palmero , Marco Bassani

Cement-stabilised subbases provide superior bearing capacity and durability to road pavements compared to unbound aggregate layers. However, stabilisation reduces the environmental benefits derived when recycled aggregates are used. This research compares alternative binders to Portland cement to highlight mechanical, environmental, and economic advantages and disadvantages in a cradle-to-production scenario. Three low-clinker cements with different proportions of pozzolana and three alkali-activated (AA) binders derived from (i) construction and demolition waste fines, (ii) municipal incinerator bottom ash and (iii) waste clay, were compared to Portland limestone cement. The compressive strength of binder pastes was measured after 7 and 28 curing days.

Pozzolanic cements proved viable alternatives to Portland ones, while AA pastes exhibited lower strengths. The crystallinity of alkali-activated silica- and alumina-rich waste precursors was responsible for their limited strength. The life cycle assessment indicated that the replacement of clinker with pozzolana significantly reduces the environmental impact. AA binders with waste precursors can reduce the environmental impact only with a limited quantity of alkaline solution. If the lower strength achieved by AA binders is compensated by adding higher quantities to recycled aggregate, the increase in environmental impact and cost would make them less competitive. The option of using AA binders would be further strengthened with the production of environmentally friendly alkaline solutions and greater local availability of amorphous precursors. At present, cements are cheaper than AA binders due to the current massive production, widespread availability, and competition between producers.

与未粘结的集料层相比，水泥稳定基层可为路面提供更高的承载能力和耐久性。然而，当使用再生骨料时，稳定化会降低环境效益。本研究对波特兰水泥的替代粘结剂进行了比较，以突出从摇篮到生产过程中的机械、环境和经济优缺点。研究人员将三种不同比例的低熟料水泥、三种碱激活（AA）粘结剂与波特兰石灰石水泥进行了比较，这三种粘结剂分别来自（i）建筑和拆除废物细粉、（ii）城市焚化炉底灰和（iii）废弃粘土。经过 7 天和 28 天的养护后，测量了粘合剂浆料的抗压强度。事实证明，波特兰水泥的替代品是可行的，而 AA 浆料的强度较低。碱激活二氧化硅和富含氧化铝的废物前体的结晶性是其强度有限的原因。生命周期评估表明，用毛石粉替代熟料可显著减少对环境的影响。使用废物前驱体的 AA 粘合剂只能通过有限数量的碱性溶液来减少对环境的影响。如果通过增加再生骨料的用量来弥补 AA 粘结剂所达到的较低强度，则环境影响和成本的增加会降低其竞争力。随着环保型碱性溶液的生产和本地无定形前体供应的增加，使用 AA 粘结剂的选择会进一步加强。目前，由于水泥的大量生产、广泛供应和生产商之间的竞争，水泥比 AA 粘结剂便宜。

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引用次数: 0

A comprehensive study on the mechanical properties of natural fiber reinforced stabilized rammed earth using experimental and data-driven fuzzy logic-based analysis 基于实验和数据驱动的模糊逻辑分析方法对天然纤维增强夯土的力学性能进行了综合研究

Cleaner Materials

Pub Date : 2025-02-16 DOI: 10.1016/j.clema.2025.100300

Aryan Baibordy, Mohammad Yekrangnia, Saeed Ghaffarpour Jahromi

This study investigated the mechanical properties of rammed earth (RE) stabilized with cement or lime and reinforced with straw. Specifically, the compressive and tensile strengths of 15 different mix designs were analyzed, including unstabilized RE, RE stabilized with lime or cement (at 4 % and 8 % by weight of soil), and RE reinforced with straw (at 0.5 % and 1.0 % by weight of soil), along with various combinations of stabilized and unstabilized RE reinforced with straw. Mechanical properties were further assessed through ultrasonic testing and scanning electron microscopy (SEM). Additionally, a data-driven fuzzy logic model was developed to estimate the mechanical properties of RE, addressing a key gap in the application of fuzzy logic to RE construction. The results showed that stabilizing RE with cement and lime increased its 28-day dry compressive strength by 365 % to 640 % and 109 % to 237 %, respectively. The addition of straw generally reduced compressive strength. The stress–strain curves indicated that the elastic modulus of RE stabilized with cement and lime increased by up to 350 % and 11 %, respectively. The 28-day dry tensile strength of the samples ranged from 0.17 to 0.56 MPa. Furthermore, the addition of stabilizers improved tensile strength by approximately 88 % to 224 %, while straw enhanced the tensile strength of unstabilized RE by about 35 %. Ultrasonic and SEM analyses provided valuable insights into the mechanical properties of RE. Additionally, the fuzzy logic model proved useful, yielding satisfactory results in predicting the properties of RE, particularly when using the centroid defuzzification method. The study concluded that RE materials when properly cured and effectively stabilized with cement, lime, and straw, can achieve acceptable mechanical properties and offer sustainable benefits.

研究了水泥、石灰稳定、秸秆加固夯土的力学性能。具体来说，分析了15种不同混合设计的抗压和抗拉强度，包括不稳定的RE，石灰或水泥稳定的RE（土壤重量的4%和8%），稻草加固的RE（土壤重量的0.5%和1.0%），以及稻草加固的稳定和不稳定的RE的各种组合。通过超声检测和扫描电镜（SEM）进一步评估了材料的力学性能。此外，开发了一个数据驱动的模糊逻辑模型来估计可再生能源的力学性能，解决了模糊逻辑在可再生能源构建中应用的关键空白。结果表明，水泥和石灰稳定稀土的28天干抗压强度分别提高了365% ~ 640%和109% ~ 237%。秸秆的加入一般会降低抗压强度。应力-应变曲线表明，水泥和石灰稳定稀土的弹性模量分别提高了350%和11%。样品的28天干抗拉强度范围为0.17 ~ 0.56 MPa。此外，稳定剂的加入使稀土的抗拉强度提高了约88%至224%，而秸秆使不稳定稀土的抗拉强度提高了约35%。超声和扫描电镜分析为稀土的力学性能提供了有价值的见解。此外，模糊逻辑模型被证明是有用的，在预测稀土的性能方面取得了令人满意的结果，特别是当使用质心去模糊化方法时。研究得出结论，当可再生能源材料经过适当的固化并与水泥、石灰和稻草有效稳定时，可以获得可接受的力学性能并提供可持续的效益。

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引用次数: 0

Comparative use of different AI methods for the prediction of concrete compressive strength 不同人工智能方法在混凝土抗压强度预测中的比较应用

Cleaner Materials

Pub Date : 2025-02-04 DOI: 10.1016/j.clema.2025.100299

Mouhamadou Amar

Concrete mix design requires specialized knowledge and techniques for characterization. However, this process is time-consuming, and the mechanical properties, such as strength, can vary due to factors like cement type, water content, aggregates, and curing time. Additionally, analytical mathematical models are often used to estimate concrete characteristics. However, accurately determining concrete properties without laboratory testing is challenging, especially when nontraditional materials, such as certain supplementary cementitious materials, are involved. Recently, artificial intelligence has become a powerful resource that enables machine learning-based forecasting using available data. This study utilized RapidMiner® software to design models capable of analyzing various types of tagged data and performing machine learning predictions. These models were applied to over 5,373 concrete formulations compiled from 137 literature sources. The simulations used artificial neural networks or deep learning, generalized linear, decision tree, random forest, support vector machine, and gradient-boosted tree models to predict the compressive strength of 8 concrete mix designs containing different SCMs. The accuracy of models was estimated using traditional statistical indices such as R², MAPE and RMSE. The most accurate model was found to be a gradient-boosted tree followed by deep learning and random forest. Forecasts were validated with high accuracy by comparing experimental results to numerical data.

混凝土配合比设计需要专门的知识和表征技术。然而，这一过程非常耗时，而且强度等机械性能会因水泥类型、含水量、骨料和养护时间等因素而有所不同。此外，分析数学模型经常用于估计具体的特性。然而，在没有实验室测试的情况下准确地确定混凝土的性能是具有挑战性的，特别是当涉及非传统材料（如某些补充胶凝材料）时。最近，人工智能已经成为一种强大的资源，可以使用可用数据进行基于机器学习的预测。本研究利用RapidMiner®软件设计能够分析各种类型标记数据并执行机器学习预测的模型。这些模型被应用于来自137个文献来源的5,373多个具体配方。模拟使用人工神经网络或深度学习、广义线性、决策树、随机森林、支持向量机和梯度增强树模型来预测包含不同SCMs的8种混凝土配合比设计的抗压强度。采用R2、MAPE、RMSE等传统统计指标对模型的精度进行估计。最准确的模型是梯度增强树，其次是深度学习和随机森林。通过实验结果与数值数据的比较，验证了预报的准确性。

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引用次数: 0

Enhancing performance of recycled aggregate concrete with supplementary cementitious materials 补充胶凝材料提高再生骨料混凝土的性能

Cleaner Materials

Pub Date : 2025-02-02 DOI: 10.1016/j.clema.2025.100298

Abba Fatiha , Ezziane Karim , Adjoudj Mhamed , Abed Farid

The substitution of natural coarse aggregates (NCA) by recycled coarse aggregates (RCA) is part of the environmental approach aimed at reducing waste and preserve natural resources. Unfortunately, RCA is of poor quality due to the presence of old mortar attached to its surface. It is characterized by its low density, high absorption, low rigidity and a poor quality interfacial transition zone (ITZ) which results in a lower quality concrete. This experimental study aims to introduce together with RCA aggregates supplementary cementitious materials (SCM) in order to reduce the decrease in mechanical performance, durability and microstructure of concrete. In a concrete based on RCA aggregates, ordinary cement was replaced with 20% natural pozzolan (NP), 10% limestone powder (LP), 20% ground granulated blast furnace slag (GGBFS) or 10% fumed silica (SF). Concrete was studied in terms of workability, superplasticizer requirements, mechanical strength, water absorption and microstructure. The results reveal that SCM significantly improves the performance of RAC concrete by promoting filling effects, nucleation, pozzolanic reactions and hydraulic activity. In the long term, RAC concrete has a 12% lower strength than OAC concrete. This decrease is reduced to only 3% when using LP and even results in 9% and 28% higher strengths when using GGBFS or SF. Similarly, an improvement in structural porosity up to 28% is observed, which led to a significant reduction in shrinkage strain, ranging from 20% to 44%.

用再生粗骨料（RCA）替代天然粗骨料（NCA）是旨在减少浪费和保护自然资源的环境方法的一部分。不幸的是，由于存在旧砂浆附着在其表面，RCA的质量很差。其特点是低密度、高吸收率、低刚度和界面过渡区质量差，导致混凝土质量较低。本试验研究旨在引入RCA骨料的补充胶凝材料（SCM），以减少混凝土的力学性能、耐久性和微观结构的下降。在基于RCA骨料的混凝土中，用20%天然火山灰（NP）， 10%石灰石粉（LP）， 20%磨粒高炉渣（GGBFS）或10%气相白炭黑（SF）代替普通水泥。从和易性、减水剂要求、机械强度、吸水率和微观结构等方面对混凝土进行了研究。结果表明，掺加SCM可显著改善RAC混凝土的填充效果、成核、火山灰反应和水力活性。从长远来看，RAC混凝土的强度比OAC混凝土低12%。当使用LP时，这种降低减少到只有3%，而当使用GGBFS或SF时，甚至会导致9%和28%的强度提高。同样，观察到结构孔隙度的改善高达28%，这导致收缩应变显著降低，从20%到44%不等。

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引用次数: 0

Selected residual biomass valorization into pellets as a circular economy-supported end-of-waste 选定的剩余生物质增值成颗粒，作为循环经济支持的废物终端

Cleaner Materials

Pub Date : 2025-01-24 DOI: 10.1016/j.clema.2025.100295

Zane Vincevica-Gaile , Maryna Zhylina , Andrei Shishkin , Linda Ansone-Bertina , Linards Klavins , Lauris Arbidans , Linda Dobkevica , Ivar Zekker , Maris Klavins

Among prospective directions to convert residual biomass into valuable products is pelleting, which can be followed by low-temperature pyrolysis, serving as an economically justified method for reducing the final waste stream. In this study, fresh and biochar pellets were obtained from selected residual biomass – waste derived from widespread industries such as energy production, food processing, and forestry and chemical processing in a mixture with peat processing residues used as a binder. Obtained pellets consisted of woody biomass ashes (ASP3 and ASP5) or coffee grounds (CSP3 and CSP5) at equal proportions mixed with spruce needles biomass (48.5 % or 47.5 %) by adding 3 % or 5 % of peat processing residues as a binder, respectively, as indicated. Biochar pellets were obtained by pyrolyzing fresh pellets at 500 °C with a heating rate of 5 °C/min. Chemical-physical properties (e.g., moisture content, ash content, chemical composition, porosity, density) of pellets were studied. The most promising for further use were assessed CSP3. In turn, ASP5 were characterized by relatively higher carbon framework density, surface area (6.889 m²/g), and water absorption (97.83 %), indicating their use as a sorbent applicable, e.g., for wastewater treatment, while others can be used in soil quality improvement and sustainable agriculture support. The conversion of residual biomass into fresh and biochar pellets serves as an efficient approach in end-of-waste following the targets of circular economy towards zero-waste production.

将剩余生物质转化为有价值产品的一个有前景的方向是造粒，然后进行低温热解，这是减少最终废物流的一种经济合理的方法。在这项研究中，新鲜和生物炭颗粒是从选定的残余生物质中获得的-来自能源生产，食品加工，林业和化学加工等广泛行业的废物，与泥炭加工残留物混合用作粘合剂。如所示，所获得的颗粒由木质生物质灰烬（ASP3和ASP5）或咖啡渣（CSP3和CSP5）以等比例混合云杉针叶生物质（48.5%或47.5%）组成，分别添加3%或5%的泥炭处理残留物作为粘合剂。在500℃下，以5℃/min的升温速率对新鲜颗粒进行热解，得到生物炭颗粒。研究了球团的化学物理性质（如水分含量、灰分含量、化学成分、孔隙度、密度）。最有希望进一步应用的是CSP3。ASP5具有较高的碳骨架密度、比表面积（6.889 m2/g）和吸水性（97.83%），可用于废水处理等吸附剂，其他可用于土壤质量改善和可持续农业支持。将剩余生物质转化为新鲜和生物炭颗粒是废物结束的有效方法，遵循循环经济实现零废物生产的目标。

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引用次数: 0

Impact of manufacturing variables on the mechanical performance of recycled glass-enhanced composites 制造变量对再生玻璃增强复合材料力学性能的影响

Cleaner Materials

Pub Date : 2025-01-22 DOI: 10.1016/j.clema.2025.100297

Nathaphon Buddhacosa , Thevega Thevakumar , Everson Kandare , Sujeeva Setunge , Dilan Robert

This study investigated the influence of various manufacturing conditions – including moulding pressure, post-curing, and aging – on the microstructure and mechanical properties (flexural and tensile) of epoxy matrix composites incorporating recovered glass particles at weight fractions ranging from 84 wt% to 90 wt%. The study focused on understanding how these conditions affect the interfacial bonding between the glass particles, epoxy matrix, and void content to establish a correlation between microstructure and mechanical performance before and after ceramification. The findings revealed that increasing moulding pressure from 1.1 MPa to 6.6 MPa reduced void content, increased composite density, and significantly improved flexural properties. The impact of post-curing on the composites’ flexural performance was also examined, and it was found that adjusting the epoxy matrix weight fraction from 6 wt% to 12 wt% further influenced the composite’s mechanical properties. X-ray computed tomography (CT) and scanning electron microscopy (SEM) analyses revealed changes in composite porosity and interfacial bonding, enabling the correlation of these microstructural changes with variations in mechanical properties for both non-ceramified and ceramified composites. Ceramification induced additional microstructural changes, including the formation of voids, which influenced the composites’ mechanical properties. Additionally, the effect of integrating steel wire mesh with 6.5 mm apertures on the mechanical performance of the glass/epoxy composites, both before and after ceramification, was explored.

本研究调查了各种制造条件（包括成型压力、后固化和老化）对含有回收玻璃颗粒的环氧基复合材料的微观结构和机械性能（弯曲和拉伸）的影响，重量分数从84 wt%到90 wt%不等。研究的重点是了解这些条件如何影响玻璃颗粒、环氧基和空隙含量之间的界面结合，以建立陶瓷化前后微观结构与力学性能之间的相关性。结果表明，将成型压力从1.1 MPa增加到6.6 MPa，可降低孔隙含量，提高复合材料密度，并显著改善弯曲性能。研究了后固化对复合材料抗弯性能的影响，发现将环氧基重量分数从6 wt%调整到12 wt%，进一步影响了复合材料的力学性能。x射线计算机断层扫描（CT）和扫描电子显微镜（SEM）分析揭示了复合材料孔隙度和界面结合的变化，使得这些微观结构变化与非陶化和陶化复合材料力学性能的变化之间存在相关性。陶瓷化引起了额外的微观结构变化，包括空洞的形成，这影响了复合材料的力学性能。此外，还探讨了6.5 mm孔径的钢丝网在陶瓷化前后对玻璃/环氧复合材料力学性能的影响。

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引用次数: 0

Carbonation reaction of recycled concrete aggregates (RCA): CO2 mass consumption under various treatment conditions 再生混凝土骨料（RCA）碳化反应：不同处理条件下的CO2质量消耗

Cleaner Materials

Pub Date : 2025-01-16 DOI: 10.1016/j.clema.2025.100296

Hossein Sousanabadi Farahani , Amin Hosseini Zadeh , Jiong Hu , Chris Hawkins , Seunghee Kim

Concrete is a key building material around the world due to its excellent strength and durability. Recycling demolished concrete for new construction materials may play a significant role in sustainable development. Producing recycled concrete aggregates (RCA) from waste concrete is one approach for such an initiative. However, using RCA may pose challenges, such as reduced density, lower elastic modulus and strength, and increased water absorption. Recently, the carbonation of RCA has emerged as a method to address those concerns. This study explores the carbon sequestration capacity of RCA through carbonation, examining various parametric conditions, including initial CO₂ pressure, relative humidity, temperature, and pre-treatment approach. Both lab-scale and large-scale carbonation tests were conducted. Additionally, a cost analysis and CO₂ footprint assessment were performed. The findings showed that applying higher initial CO₂ pressures (e.g., 40–60 psi) and optimal relative humidity (∼55 %) could significantly enhance the carbonation efficiency of RCA. Elevating temperature also led to accelerated CO₂ consumption, being more effective on the lab scale. The economic analysis presented potential cost benefits when substituting natural aggregates with CO₂-treated RCA. All in all, these results suggest that the carbonation of RCA may provide significant environmental benefits through carbon sequestration, promoting sustainable construction practices.

混凝土因其优异的强度和耐久性而成为世界各地的关键建筑材料。回收拆除的混凝土作为新的建筑材料可能在可持续发展中发挥重要作用。从废混凝土中生产再生混凝土骨料（RCA）是实现这一倡议的一种方法。然而，使用RCA可能会带来一些挑战，例如密度降低、弹性模量和强度降低、吸水率增加。最近，RCA的碳酸化已经成为解决这些问题的一种方法。本研究通过考察初始CO2压力、相对湿度、温度和预处理方法等参数条件，探讨了RCA的固碳能力。进行了实验室规模和大规模的碳酸化试验。此外，还进行了成本分析和二氧化碳足迹评估。研究结果表明，施加较高的初始CO2压力（例如，40-60 psi）和最佳相对湿度（~ 55%）可以显著提高RCA的碳化效率。升高的温度也导致二氧化碳消耗加速，在实验室规模上更有效。经济分析表明，用co2处理的RCA代替天然骨料具有潜在的成本效益。总而言之，这些结果表明，RCA的碳化可以通过固碳提供显著的环境效益，促进可持续建筑实践。

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引用次数: 0

Self-cleaning stone Façades using TiO2 Microwave-Synthesised Coatings 使用TiO2微波合成涂层的自清洁石材表面

Cleaner Materials

Pub Date : 2025-01-11 DOI: 10.1016/j.clema.2025.100294

David Henriques Bento , Maria Leonor Matias , Maria Magalhães , Catarina Quitério , Ana Pimentel , Dora Sousa , Pedro Amaral , Carlos Galhano , Elvira Fortunato , Rodrigo Martins , Daniela Nunes

This study explores the development and characterization of self-cleaning coatings using titanium dioxide (TiO₂) nanoparticles for natural stone façades, particularly limestone. An energy-efficient, eco-friendly, fast (30 min), and low temperature (110 °C) microwave-assisted solvothermal method is reported for synthesising TiO₂ nanoparticles. These nanoparticles were integrated into coatings that were further applied to limestone substrates via spray-coating, maintaining the stone’s appearance while enhancing its self-cleaning properties. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), UV–VIS spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis were used to fully characterize the nanopowder. The anatase phase of TiO₂ nanoparticles and a band gap energy of about 3.24 eV were confirmed. SEM and STEM observations revealed that the nanopowder is formed by spherical particles with very fine nanocrystals highly agglomerated, however ensuing a high specific surface area of 199 m²/g. The self-cleaning properties of the coated limestone were assessed using static contact angle measurements. The results showed a significant enhancement in hydrophilicity, with the static contact angle of the coated limestone substrate reducing to nearly zero even without UV exposure, indicating complete wettability. The coating was also subjected to adhesion tests, confirming the presence of TiO₂ nanoparticles even after multiple cycles. The photocatalytic activity of the developed coating was evaluated using rhodamine B and methyl orange as model pollutants under solar radiation. The coating effectively degraded both model pollutants, and the photocatalytic cycling tests revealed a stable performance after multiple cycles. This research provides a promising approach for creating sustainable and low-maintenance building materials, contributing to preserving natural stone façades and reducing environmental impact in the construction industry.

本研究探讨了使用二氧化钛（TiO2）纳米颗粒用于天然石材表面，特别是石灰石的自清洁涂层的开发和表征。报道了一种高效、环保、快速（30 min）、低温（110℃）的微波辅助溶剂热合成TiO2纳米颗粒的方法。这些纳米颗粒被整合到涂层中，通过喷涂进一步应用于石灰石基底，在保持石材外观的同时增强其自清洁性能。利用x射线衍射（XRD）、扫描电子显微镜（SEM）、扫描透射电子显微镜（STEM）、能量色散x射线能谱（EDX）、紫外-可见光谱（UV-VIS）和布鲁诺尔-埃米特-泰勒（BET）表面积分析等表征技术对纳米粉体进行了全面表征。结果表明，TiO2纳米颗粒为锐钛矿相，带隙能约为3.24 eV。SEM和STEM观察表明，纳米粉末是由非常细的纳米晶体高度团聚的球形颗粒形成的，但具有199 m2/g的高比表面积。采用静态接触角测量方法对涂层石灰石的自清洁性能进行了评价。结果表明，涂层后的石灰石基材的亲水性显著增强，即使没有紫外线照射，其静态接触角也几乎为零，表明其具有完全的润湿性。涂层还进行了附着力测试，即使在多次循环后也证实了TiO2纳米颗粒的存在。以罗丹明B和甲基橙为模型污染物，对所制备的涂层在太阳辐射下的光催化活性进行了评价。该涂层可有效降解两种模式污染物，并且经过多次循环的光催化循环测试表明其性能稳定。这项研究为创造可持续和低维护的建筑材料提供了一种有前途的方法，有助于保护天然石材立面，减少建筑行业对环境的影响。

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引用次数: 0

Fiber-reinforced geopolymers made with recycled aggregates for screed flooring and repair applications 由再生骨料制成的纤维增强地聚合物，用于地坪和修复应用

Cleaner Materials

Pub Date : 2025-01-08 DOI: 10.1016/j.clema.2025.100293

Joud Hwalla , Hilal El-Hassan , Joseph J. Assaad , Tamer El-Maaddawy

The increase in greenhouse gas emissions from cement production, along with limited landfill capacity for construction waste, has driven research into finding sustainable alternatives to replace cement and natural aggregates. While cement replacement with geopolymeric binders in mortar and concrete has been proven feasible, replacing natural aggregates with recycled counterparts has led to performance losses. To offset this drawback, different additives, including fibers, have been incorporated into such construction materials. This study evaluates the feasibility of using steel fiber (SF)-reinforced geopolymer (GP) composites incorporating recycled fine aggregates (RFA) for screed flooring and repair applications. GP mixes were prepared with RFA mass substitution up to 100 %, alongside SF volume of 0.5 % and 1 %. Flow values of 125 ± 25 mm were attained within 35 to 70 min. The 7-day compressive strength of GP composites reached 74.0 % to 96.2 % of their 28-day values. RFA substitution reduced compressive strength, elastic modulus, tensile strength, pull-off bond strength, and energy absorption and increased impact indentation and abrasion mass loss by up to 56, 69, 60, 23, 68, 266, and 2025 %, respectively. Conversely, SF addition improved most of these properties except for compressive and pull-off bond strength, which slightly decreased. GP composites made with 0 %, 25 %, and 50 % RFA satisfied the strength requirements for use in structural repair, while those with higher RFA replacement were suitable for non-structural use. Based on BS 8204, GP mixes were categorized as Category A screed flooring except the plain mix made with 100 % RFA, which was categorized as Category B.

水泥生产产生的温室气体排放量增加，加上建筑垃圾填埋能力有限，促使研究人员寻找替代水泥和天然骨料的可持续替代品。虽然用砂浆和混凝土中的地聚合物粘结剂替代水泥已被证明是可行的，但用回收的天然骨料替代天然骨料会导致性能损失。为了弥补这一缺点，不同的添加剂，包括纤维，已经加入到这种建筑材料中。本研究评估了将含再生细骨料（RFA）的钢纤维（SF）增强地聚合物（GP）复合材料用于地坪和修复应用的可行性。制备了RFA质量取代率为100%、SF体积为0.5%和1%的GP混合料。在35 ~ 70 min内达到125±25 mm的流量值。GP复合材料的7天抗压强度达到其28天值的74% ~ 96.2%。RFA替代降低了抗压强度、弹性模量、拉伸强度、脱粘强度和能量吸收，并使冲击压痕和磨损质量损失分别增加了56%、69%、60%、23%、68%、266和2025 %。相反，SF的加入提高了除抗压和拉脱粘结强度外的大部分性能，这两个性能略有下降。RFA含量为0%、25%和50%的GP复合材料满足结构修复的强度要求，而RFA含量较高的GP复合材料适用于非结构用途。基于BS 8204， GP混合料被归类为A类地坪，而100% RFA混合料被归类为B类地坪。

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引用次数: 0

Concrete carbon mixing – A systematic review on the processes and their effects on the material performance 混凝土碳混合。系统地回顾了混合过程及其对材料性能的影响

Cleaner Materials

Pub Date : 2025-01-05 DOI: 10.1016/j.clema.2025.100292

Marco Davolio, Giovanni Muciaccia, Liberato Ferrara

The need for concrete industry to meet the climate neutrality target raised the attention towards carbon capture and utilization (CCU) technologies. Among the various solutions, cementitious materials can benefit from enforced carbonation, a thermodynamically stable reaction that permanently sequesters carbon dioxide into cement compounds. A possible enforced carbonation process is concrete carbon mixing, which involves the addition of pumping systems into concrete production lines to inject carbon dioxide into the material while in a fresh state. Various studies attempted to improve the efficiency of the process and to increase the quantity of fixed carbon dioxide. The current literature was systematically analysed to provide an overview of process parameters, possible injection systems, and properties of carbonated cementitious products. The studies were classified according to the injection stage: carbonation of the mixing water, carbonation of the cement slurry, or injection during concrete mixing with all the components. Concrete carbon mixing has proven to be promising for carbon dioxide sequestration through enforced carbonation, as the injection process enhanced the properties of the final product in most instances. In addition, other relevant aspects of carbon dioxide sequestration processes were discussed. Firstly, the methods and formulations to determine the CO₂ uptake were presented together with cross-comparison studies. Moreover, the methodological aspects of life cycle assessment (LCA) applied to concrete carbon mixing processes were discussed, showing the lack of systematic studies. In conclusion, simplified evaluations demonstrated the economic viability of carbon dioxide injection in fresh concrete, supporting future industrial deployment and discussing the challenges for the upscaling.

混凝土行业实现气候中和目标的需要引起了对碳捕获和利用（CCU）技术的关注。在各种解决方案中，胶凝材料可以受益于强制碳化，这是一种热力学稳定的反应，可以将二氧化碳永久地隔离到水泥化合物中。一种可能的强制碳化过程是混凝土碳混合，这涉及到在混凝土生产线上增加泵送系统，在新鲜状态下将二氧化碳注入材料。各种各样的研究试图提高这一过程的效率，并增加固定二氧化碳的数量。目前的文献被系统地分析，以提供工艺参数的概述，可能的注射系统，和碳酸化胶凝产品的性质。这些研究根据注入阶段进行了分类：混合水的碳化，水泥浆的碳化，或在混凝土搅拌过程中注入所有组分。混凝土碳混合已被证明有希望通过强制碳化来封存二氧化碳，因为在大多数情况下，注入过程增强了最终产品的性能。此外，还讨论了二氧化碳固存过程的其他相关方面。首先，介绍了测定CO2吸收量的方法和公式，并进行了交叉比较研究。此外，还讨论了应用于混凝土碳搅拌过程的生命周期评估（LCA）的方法学方面，表明缺乏系统的研究。总之，简化的评估证明了在新混凝土中注入二氧化碳的经济可行性，支持了未来的工业部署，并讨论了升级的挑战。

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引用次数: 0