Controlled low-strength material incorporating recycled fine aggregate from urban red brick based construction waste

Sixteen controlled low-strength material( CLSM)mixtures with various cement-to-sand( C/Sa) ratios and water-to-solid( W/So) ratios were prepared using recycled fine aggregate from urban red brick based construction waste.The fluidity and bleeding of the fresh CLSM mixtures were measured via the modified test methods, and the hardened CLSM mixtures were then molded to evaluate their compressive strength and durability. The results showthat the fluidity of the fresh CLSM mixtures is 105 to 227 mm with the corresponding bleeding rate of 3. 7% to 15. 5%, which increases with the increase in fluidity. After aging for 28 d,the compressive strength of the hardened CLSM mixtures reaches 1. 15 to 13. 96 M Pa, and their strength can be further enhanced with longer curing ages. Additionally, the strength increases with the increase of the C/Sa ratio, and decreases with the increase of the W/So ratio under the same curing age. Based on the obtained compressive strength, a fitting model for accurately predicting the compressive strength of the CLSM mixtures was established, which takes into account the above two independent variables( C/Sa and W/So ratios).M oreover, the durability of the hardened CLSM mixtures is enhanced for samples with higher C/Sa ratios.

Properties of Rapid Hardening Controlled Low Strength Material Made of Recycled Fine Aggregate from Urban Red Brick Construction Waste

In some cases of emergency backfill engineering projects, traditional backfill materials cannot meet the requirements of fast construction due to their long curing time. This study presents a new kind of rapid hardening controlled low strength material, which utilizes both rapid hardening sulphoaluminate cement and recycled fine aggregate from urban red brick construction waste. Totally, sixteen mixtures were prepared for the experiment with different cement-to-sand ratios and water-to-solid ratios. The flowability and bleeding rate of fresh mixture were measured to evaluate its workability, and the compressive strength of hardened mixture was tested to evaluate its rapid hardening and mechanical properties. Test results indicate that rapid hardening controlled low strength material containing recycled fine aggregate from urban red brick construction waste can achieve the desirable flowability, but the bleeding rate increases with the increase of flowability. In addition, 2-hour compressive strength can reach 0.08 - 0.12 MPa, and 4-hour compressive strength is 0.32 - 1.54 MPa, which can meet the requirements of emergency backfill construction. At last, based on the derived compressive strength, a fitting model for predicting compressive strength evolution of this new rapid hardening backfill material is developed, which fits accurately with these experimental data.

Partial Replacement of Cement by Solid Wastes as New Materials for Green Sustainable Construction Applications

The manufacturing of ordinary Portland cement is an energy-intensive process that results in pollution and CO2 emissions,among other issues.There is a need for an environmentally friendly green concrete substitute.Waste products from a variety of sectors can be recycled and used as a green concrete substitute.This decreases the environmental effects of concrete manufacturing as well as energy consumption.The use of solid waste materials for green building is extremely important now and in the future.Green concrete is also in its infancy in terms of manufacturing and application.Academics must intervene by encouraging business implementation.The aim of this review paper is to raise awareness about the importance of repurposing recycled materials and to highlight new technologies for producing green,sustainable concrete.

Application of Construction Waste Recycled Material Processing in Road Engineering

In order to promote the recycling of construction waste in China and reduce the cost of road engineering materials,this paper expounds on the technical indexes,road performance,durability,and the impact on the compressive strength of road engineering of construction waste recycled materials based on the analysis of the processing technology of construction waste recycled materials to provide reference for future research.

Construction utilization of foamed waste glass

Foamed waste glass(FWG) material is newly developed for the purpose to utilize the waste glassware and other waste glass. FWG has a multi-porous structure that consists of continuous or discontinuous voids. Hence lightweight but considerable stiffness can be achieved. In the present study, the manufacture and engineering properties of FWG are introduced first. Then, the utilizations of FWG are investigated in laboratory tests and field tests. Some case studies on design and construction work are also reported here. Through these studies we know that the discontinuous void material can be utilized as a lightweight fill material, ground improvement material and lightweight aggregate for concrete. On the other hand, the continuous void material can be used as water holding material for the greening of ground slope and rooftop, and as clarification material for water.

Identification of Glass Powders and Sands from the Crushing of Glass Waste from the City of Loméin Togo

The sustainability of a city depends on the effective and efficient management of its solid waste. Waste recycling channels mainly process glass bottles for direct reuse. Some of these sectors carry out the crushing and grinding of end-of-life glass waste for use in civil engineering without the identification in terms of building materials being clearly established. The present study therefore aims to determine the physical and chemical characteristics of glass powders and sands resulting from the crushing and grinding of glass waste from Grand Lomé in Togo in order to consider their granular potential. Samples of sand and glass powder from the crushing and grinding of white, brown and green glass were subjected to characterization tests in the laboratory followed by analysis of the granular parameters and their modeling by Weibull’s law. The results show that the powder and the glass sand contain a high proportion of silica (SiO2) ranging from 69.11% to 70.18% and a low proportion of alumina (Al2O3) (less than 0.07) and iron (Fe2O3) (lower to 1.09). These three materials have tight and male graded grain sizes (Cu Cc omogeneous (k < 2.89). The absolute density (2 dab < 3) and the fineness modulus (Mf 2.1) make these materials probable aggregates for plaster and coating mortars. Nevertheless, an in-depth study will be made to determine a suitable formula.

Biochar as construction materials for achieving carbon neutrality

Biochar is a waste-derived material that can sequester carbon at a large scale.The development of low-carbon and sustainable biochar-enhanced construction materials has attracted extensive interest.Biochar,having a porous nature and highly functionalised surface,can provide nucleation sites for chemical reactions and exhibit compatibility with cement,asphalt,and polymer materials.This study critically reviewed the state-of-the-art biochar-enhanced construction materials,including biochar-cement composites,biochar-asphalt composites,biochar-plastic composites,etc.The efficacies and mechanisms of biochar as construction materials were articulated to improve their functional properties.This critical review highlighted the roles of biochar in cement hydration,surface functional groups of engineered biochar for promoting chemical reactions,and value-added merits of biochar-enhanced construction materials(such as humidity regulation,thermal insulation,noise reduction,air/water purification,electromagnetic shielding,and self-sensing).The major properties of biochar are correlated to the features and functionalities of biochar-enhanced construction materials.Further advances in our understanding of biochar’s roles in various composites can foster the next-generation design of carbon-neutral construction materials.

Semi-flowable self-consolidating concrete using industrial wastes for construction of rigid pavements in India:An overview

The construction of rigid pavements using conventionally vibrated concrete consumes a significant amount of energy as it requires rigorous vibrations.This also requires a high number of laborers and creates noise during construction.Thus,a new kind of concrete called semi-flowable self-consolidating concrete(SFSCC)for pavement construction using slip-form paving technology is reviewed in this article.The SFSCC requires no energy for compaction as it gets compacted under its self weight.It also renders shape stability in the fresh state which is critical to expedite the construction in slip form concreting.The review focuses on the need,evolution,and requirement of the ingredient materials,mix design,and methods for testing the properties of SFSCC.Further,the utilization of industrial wastes in the construction industry and the production of self-consolidating concrete are discussed.The literature on the effect of different materials on the properties of such concrete and field studies in this context are discussed.Lastly,its suitability as pavement construction material either in normal rural roads or in low-volume village roads is discussed in the Indian context.The review reveals that relatively less amount of study on SFSCC in general and as a pavement material in particular is available in the literature and pursuant to this,creates a wide scope of research.

煤矸石-建筑固废砖填充材料正交试验及性能研究

利用正交试验设计(4因素4水平)对煤矸石-建筑固废砖填充材料(以下称膏体填充材料)的流动性与强度进行了测试。研究了粉煤灰掺量、废砖骨料取代率、质量浓度、减水剂掺量对膏体填充材料的坍落度、扩展度和早、中、后期抗压强度以及劈裂抗拉性能的影响,确定膏体填充材料的最优配合比,并对试验结果进行系统性分析。结果表明:各个因素对膏体填充材料流动性的影响显著,可总结为流动性随粉煤灰掺量、废砖骨料取代率、质量浓度的增加而下降,随减水剂掺量的增加而上升;各个因素对膏体填充材料早期抗压强度无明显影响;废砖取代率与减水剂掺量对膏体填充材料中、后期强度有一定的影响,当废砖骨料替代率为50%~75%、减水剂掺量为0.6%时,膏体填充材料抗压强度更高;粉煤灰掺量17%、废砖骨料取代率75%、质量浓度81%、减水剂掺量0.6%为最优组合。对选定方案的填充材料进行了微观形貌测试,说明该组合下配制出来的煤矸石膏体填充材料能保证强度,综合性能最佳。

一种基于LC-BoVW模型的建筑垃圾物料识别算法

针对建筑垃圾物料的种类多、形貌易混淆等问题,构建了一种基于局部约束的视觉词袋(local constraint-bag of visual words,LC-BoVW)模型的建筑垃圾物料识别算法。首先,对建筑垃圾物料图像分块,分别提取局部颜色特征和局部二值模式特征;考虑到图像分块特征的局部相似特性,构建LC-BoVW模型分别对目标图像的显著特征进行统计。然后,基于信息融合思想对特征统计量进行融合,形成图像的判别性特征并输入到分类器中进行物料的精确识别。最后,利用自建的5类建筑垃圾物料图像数据集进行实验,实验结果表明,所提算法能够快速有效地实现建筑垃圾物料识别,平均识别准确率可达到97.92%。

砂质土与建筑垃圾制备可控性低强度材料

利用砂质土与建筑垃圾细骨料复掺制备可控性低强度材料(CLSM),研究了砂质土与建筑垃圾细骨料不同质量比下CLSM的流动度、泌水率、凝结时间和抗压强度的变化规律,并通过XRD和SEM探究物相组成和微观形貌。结果表明,随着砂质土与建筑垃圾细骨料质量比的降低,CLSM的泌水率及流动度减小、凝结时间缩短、抗压强度提高。利用砂质土与建筑垃圾细骨料复掺解决了泌水率高的问题,且当两者质量比为1∶1时,流动度、泌水率、凝结时间和抗压强度符合市政管道回填施工要求。

安徽地区建筑垃圾资源化利用路径与处置工艺设计探讨

城市拆旧建新的过程会产生大量的建筑垃圾,如果不能及时、妥善地处理这些垃圾,不仅占用土地、污染环境,还会引发诸多社会问题。基于对安徽地区建筑垃圾资源化处置现状实地调研,发现现有的技术方案存在垃圾种类混杂、难以共线生产等问题。针对此,提出了三位一体建筑垃圾处理方案,并构建了建筑垃圾全链条管理服务平台的全新策略;同时,探讨了高品质再生骨料生产过程中的分选与提纯新工艺,推广了再生环保仿石砖生产新技术,为安徽地区乃至全国范围的建筑垃圾资源化利用和无害化处置提供可行的技术支持和决策参考。

我国废弃物循环利用体系建设路径与发展建议

废弃物循环利用是我国可持续发展的重要组成部分,是国家发展规划的重要战略任务之一。本文梳理了我国废弃物循环利用的主要成效与未来发展趋势,辨识了废弃物循环与减污降碳协同潜力未充分发挥、技术创新和研发力度不足、可持续商业模式缺乏、标准认证体系不规范、现有法律法规和标准体系建设协同性不足等问题。在此基础上,针对新能源固废、废弃高分子材料、工业固废跨产业协同、城市多源废弃物耦合4个废弃物循环利用的重点领域,从源头建立绿色生产和设计体系、优化回收过程网络、促进废弃物产品再利用和服务创新3个角度,进一步提出了各重点领域全过程的废弃物循环利用体系建设路径与主要任务。为推动我国废弃物循环利用体系的高质量建设,本文从循环与减污降碳协同增效、重大技术研发与产业化、激发再生产品的提质升级与规模化应用、助力废弃物循环利用的智能化精细化管控、加强要素保障等方面提出了发展建议。

建筑垃圾在再生建材领域资源化利用——以济南市某建筑垃圾资源化处理厂为例

建筑垃圾资源化利用是推动建筑行业可持续发展和资源循环利用的重要措施。本文介绍了通过对废弃建筑材料进行分类、回收和再加工,可以将建筑垃圾转化为具备一定性能的再生建材。并以济南市某建筑垃圾资源化处理厂为例,分析了建筑垃圾在再生建材领域资源化利用的方向及应用案例,供相似工程借鉴参考。

辽宁省新型墙体材料的革新与应用

目前,我国作为资源消耗大国,在环境保护、资源利用和能源供给都面临着越来越大的挑战。墙体材料是建筑领域不可或缺的一部分,对墙体材料开展创新研发并推广应用,可有效减少资源浪费和对环境的破坏。以辽宁省为例,介绍了新型墙体材料的概念及特点,并对新型墙材的研发应用展开一系列探讨。

建筑垃圾在我国墙体材料中的研发与资源化利用现状

建筑垃圾在墙材制品资源化利用方面的研发成了行业关注的热点之一。据统计,2020年我国建筑垃圾产量约35亿t。面对如此大量的建筑垃圾,如果不能进行资源化开发和利用,就会对土地环境造成污染。墙体材料是建筑垃圾产业化利用的重要途径之一,基于此,就建筑垃圾在我国墙体材料中的应用及研究创新成果方面进行了简要整理汇总和分析讨论。

基于建筑废物的人工湿地除磷滤料的制备及其性能

高效、高容量的吸附滤料是提高人工湿地除磷效率的重要手段。以建筑废物(废混凝土和废泡沫砖)为主要原料制备多孔除磷滤料,采用X射线衍射和扫描电子显微镜对滤料主要化学组分和形貌特征进行表征,利用吸附动力学和吸附等温线试验、静态对比试验和动态试验评估了滤料对水中磷的吸附性能。结果表明:该滤料比表面积大、孔隙发达,内部微观结构为片层孔隙结构,比表面积为22.7 m^(2)/g;其吸附过程满足拟二级吸附动力学模型和Langmuir吸附等温模型,吸附机理以单分子层物理和化学复合吸附为主,最大吸附容量达到693.21 mg/g。在总磷浓度为0.4 mg/L的静态吸附试验中,多孔滤料在4 h内对磷的平均去除率为65.38%,分别是废混凝土、废泡沫砖、陶粒、硅藻土和活性炭的4.10、1.98、3.52、2.29和1.59倍。在模拟水平流潜流湿地动态试验中,在进水总磷浓度为0.40 mg/L,水力负荷为0.48、0.96、1.20、2.40 m^(3)/(m^(2)·d)的条件下,多孔滤料对总磷的平均去除率分别为95.74%、93.56%、80.42%、55.34%;在水力负荷为0.96 m^(3)/(m^(2)·d)、进水平均总磷浓度为0.52 mg/L、连续进水45 d条件下,多孔滤料对总磷的平均去除率为92.65%。该滤料制备方法简单,除磷性能优异,还实现了对建筑废物的有效利用,作为人工湿地填料具有应用潜力。

多雨地区建筑垃圾路基填料长期变形特性研究

为探究建筑垃圾再生材料对于多雨地区城市道路路基填料的适用性,借助人工初拣、筛分试验明确再生料的物质组成,借助点荷载试验研究水分对砖块强度特性的影响,并根据原材料基本特性对路基填料级配进行设计;采用自行设计的室内大型土柱试验对浸水-失水循环过程中模型含水率与变形特性进行研究,对试验前后的再生材料回弹模量和级配进行分析。结果表明:所获取的建筑垃圾原材料以废弃砖、混凝土块及石块为主,天然级配不良;将粒径为0~10 mm、10~20 mm的两档再生材料按照3∶1的质量比掺配后的填料级配良好;路基模型经多次浸水-失水循环后最终变形量为填高的0.62%;多次循环后回弹模量衰减率为28.4%,仍满足填筑要求;在荷载和水分共同作用下,粒径大于5 mm的颗粒二次破碎情况明显,而小于0.3 mm的颗粒较为稳定,破碎后的填料级配仍满足规范要求;该级配下建筑垃圾作为路基填料在经多次浸水-失水循环后保持着良好的强度和水稳定性,可用于路基填筑。

再生料路基填筑施工工艺在高速公路中的应用

为研究再生料路基填筑施工工艺在高速公路中的应用,论文结合实际工程,阐述了建筑废弃物再生料的工程特性,重点研究了建筑废弃物再生料路基施工技术要点,并对其施工质量进行现场检测。

建筑垃圾再生微粉资源化利用研究进展

建筑垃圾再生微粉的循环利用,有助于生态环境保护与资源可持续利用,是建筑业领域实现“双碳”的一个重要途径。本文介绍了建筑垃圾再生微粉的资源化利用现状,探讨了将建筑垃圾再生微粉技术应用到黄泛区软土改良的可行性,旨在为建筑垃圾再生微粉的高效利用与深入研究提供有价值的借鉴与参考。