再生混凝土的物理力学性能研究

废弃的混凝土造成巨大的材料浪费和环境污染。为了研究废弃混凝土再生的可行性。文章利用废弃的混凝土作为粗骨料制作再生混凝土，进行物理力学性能实验，与天然骨料制成的普通混凝土进行对照。结果表明：一次再生和二次再生混凝土与对照混凝土具有相同的力学性能；一次再生和二次再生混凝土的抗压强度略高于对照混凝土；与对照混凝土相比，再生混凝土的密度有所降低，差异随着循环次数的增加而增加。研究结果为废弃混凝土的再生利用提供参考。     

黏土砖再生粗骨料混凝土构件受力及形变分析

研究黏土砖再生粗骨料混凝土的力学性能,设计对比试验。制作普通混凝土短肢抗震墙与30%的黏土砖再生粗骨料混凝土短肢抗震墙,施加低周反复载荷,分析抗震墙的承载力、延性能力、滞回曲线变化、裂缝位置及发育等评价参数,探究黏土再生粗骨料混凝土短肢抗震墙的受力性能。最终得到黏土砖再生粗骨料混凝土构件完全可用于建筑结构中,具有一定的推广价值。     

基于数字图像处理技术的再生混凝土数值模拟

为了研究骨料形态对再生混凝土材料力学性能的影响,基于势能原理的基面力元法,利用图像处理技术和MATLAB软件,建立了再生混凝土真实骨料细观模型。应用FORTRAN分析软件对再生混凝土试件进行单轴拉伸试验的数值模拟,研究了真实骨料细观模型再生混凝土宏观应力-应变曲线变化规律和试件的破坏形态。结果显示,真实骨料模型得到的宏观应力-应变曲线和试验曲线吻合度较高,骨料形状对试件的破坏形态影响较小。模型可真实地模拟再生混凝土在单轴拉伸作用下的损伤破坏过程,准确地反映试件的实际骨料形态。     

考虑取代率和砖骨料品质的再生混凝土抗压强度计算方法

砖骨料再生混凝土的粗骨料表面存在硬化砂浆和大量的界面结构,致使其抗压强度较普通混凝土的有所降低,为探究其受压破坏情况,采用多种强化方式的砖骨料,制备不同取代率的再生混凝土,引入砖骨料吸水率等特征参数,提出了一个可广泛应用的再生混凝土抗压强度计算公式。研究表明,再生混凝土的抗压强度与取代率、胶水比呈线性关系,不同强化处理方式对再生混凝土抗压强度影响显著;与试验结果相比,基于表观密度、骨料品质和取代率所建立的抗压强度公式计算误差较小,考虑影响相表观密度的计算式绝对误差平均值为5%,具有较高的精度和较好的适用性,可为其在绿色建材领域中的应用提供一定参考。     

基于生命周期理论评价建筑物能耗及环境影响

生命周期评价方法（LCA）能够分析整个建筑物各个环节对全社会的能耗和环境的影响,其分析结果可使项目各参与者清楚地了解建设项目各环节的能耗和环境影响。借助生命周期评价方法研究江苏某教学楼从原材料生产到建筑物修建完成整个过程中的能耗及环境影响,发现合理地利用分析结果有助于优化项目的设计、生产和运输方案。从节约资源、能源,保护环境的角度出发提出了扩大生命周期评价方法应用领域的研究方向。     

混合粒化高炉矿渣再生骨料混凝土的抗冻融性研究

为了保证严寒地区建筑结构的冻融安全性,对水灰比(W/C)为47%的粒化高炉矿渣混合再生骨料混凝土进行研究,通过多组试验对混合混凝土的泌水性、抗压强度等进行评估,分析混合粒化高炉矿渣的再生骨料混凝土的抗冻融性。结果表明:1)当粒化高炉矿渣掺量小于50%时,其泌水性可保持在0.1 cm~3/cm~2以下;2)在混凝土的空隙通过性试验中,掺入粒化高炉矿渣后,混凝土的间隙通过性突出,抗压强度低于普通混凝土,但具有足够的抗冻融性能;3)在配合比设计为正常强度范围的混凝土中,利用粒化高炉矿渣取代50%以下的碎砂的再生骨料混凝土具有足够的泌水性、抗压强度,以及抗冻融性能。混合粒化高炉矿渣的再生骨料混凝土可用于在高寒地区进行的工程建设,研究成果可有效提高高寒地区建筑物的抗冻融性并延长其使用寿命,可为高寒地区工程项目中抗冻融混凝土的制备提供一定的参考。     

粉煤灰再生混凝土用于道路修补的经济分析

随着我国经济快速发展,道路的运输荷载日益增大,使得一些道路状况逐渐变差,道路的修补费用也日益增大.本文将粉煤灰再生混凝土作为道路修补材料,分析在道路使用全寿命周期内经济可行性.认为采用粉煤灰再生混凝土修补道路不仅可以节省大量的后期成本,减少对周围环境的污染,而且在一定程度上使废弃混凝土的堆放处理问题得到解决,是一种很好的道路修补材料.     

基于界面等效模型的再生混凝土基面力元分析

从细观角度分析再生混凝土的力学特性,以往都是将再生混凝土视为由骨料、新砂浆、新界面、老砂浆、老界面五相介质组成的复合材料来分析,为了简化这种常规五相再生混凝土模型,提出了基于界面等效模型的再生混凝土基面力元分析方法。首先运用三相球理论模型将再生混凝土中的老砂浆、新界面、老界面三相介质等效成一种介质,得到三相介质的再生混凝土界面等效模型;然后利用势能原理的基面力元法编制出损伤基面力元程序,对不同尺寸的再生混凝土试块进行单轴拉伸试验模拟。给出了应力-应变曲线及破坏过程图,并与普通五相模型进行了对比,两种曲线基本吻合。因此,等效模型可以代替普通五相模型,从而简化多相再生混凝土的损伤分析,提高模拟效率。     

基于树脂聚酯的生命周期碳排放评价

为了减少聚酯树脂产品在生命周期过程中造成环境污染,文章应用生命周期评价(LCA)方法,主要分析了聚酯树脂在原材料获取阶段、生产制造阶段、运输阶段的碳排放当量。通过聚酯树脂(产品)环境影响评估软件,建立了聚酯树脂产品的生命周期模型。结果表明:聚酯树脂产品对环境造成的主要影响中,在生产制造阶段影响最大,其次是原材料获取阶段、运输阶段。最后对聚酯树脂生命周期的各个阶段提出了改进方案。     

常用缓冲包装材料的生命周期评价研究现状

生命周期评价(LCA)是目前最具有说服力的量化评价环境影响的方法,可对整个过程中可能发生资源消耗和环境污染物排放的环节进行量化分析,从而确定该种产品是否对环境产生负担,并能直观地了解到这种负担的多少。LCA作为一种评价产品、工艺过程或活动的有用的环境管理工具,目前已被政府和企业广泛采用。本文总结了瓦楞纸、发泡聚苯乙烯、聚乙烯的生命周期评价研究现状,并给出建议。     

初探国外废旧纺织品回收再利用发展现状

大量的废旧纺织品不仅造成资源的浪费,也带来了一系列环境问题。通过阐述德国、英国、日本、美国等国家的废旧纺织品回收再利用现状和主要的回收再利用方式及数量,还有相应各国的循环经济相关政策,为进一步推动我国废旧纺织品的循环利用提供参考和借鉴。     

Organizational antecedents of environmental responsiveness in industrial new product development

The greening of new product development process has been under scrutiny by researchers, but the attention has been limited to consumer products. Based on a survey, this paper investigates the environmental responsiveness in industrial new product development in 82 industrial firms. In comparison to traditional NPD process in the extant literature, the findings revealed additional activities in the greening of industrial NPD. These activities fall under the broader scope of life cycle assessment (LCA) for environmental impact including supplier evaluation and design for environment issues. The paper also investigates the relative impact of organizational antecedents on greening of industrial NPD activities. Organizational antecedents include functional interface of environmental specialists with design and product managers, environmental product policy, and top management support.     

Design of sustainable supply chains under the emission trading scheme

Increase in environmental concerns together with legislations are forcing industries to take a fresh look at the impact of their supply chain operations on the environment. This paper introduces a mixed-integer linear programming based framework for sustainable supply chain design that considers life cycle assessment (LCA) principles in addition to the traditional material balance constraints at each node in the supply chain. Indeed, the framework distinguishes between solid and liquid wastes, as well as gaseous emissions due to various production processes and transportation systems. The framework is used to evaluate the tradeoffs between economic and environmental objectives under various cost and operating strategies in the aluminum industry. The results suggest that current legislation and Emission Trading Schemes (ETS) must be strengthened and harmonized at the global level in order to drive a meaningful environmental strategy. Moreover, the model demonstrates that efficient carbon management strategies will help decision makers to achieve sustainability objectives in a cost-effective manner.     

初探国内外废旧服装回收再利用发展现状

基于废旧衣物的回收再利用角度出发,大量的废旧纺织品以及废旧服装被当作垃圾掩埋、焚烧,这既造成了资源浪费,同时也污染了环境。以探讨国内废旧服装回收再利用发展现状为主要研究对象,通过阐述国内外主要回收方式、回收模式、以及产生的社会效应以及相关国家循环政策,对我国废旧服装回收再利用发展现状做一个再思考和研究,为推动我国废旧服装回收再利用提供参考和依据。     

消费者为什么选择循环行为——城市消费者循环行为影响因素的实证研究

本文通过问卷调查，对城市消费者循环行为（包括购买行为和使用行为）的影响因素进行实证检验。结果表明，城市消费者的循环行为主要取决于垃圾问题感知、垃圾循环知识、垃圾责任意识、个人消费观念和年龄五个变量。可见．用心理意识因素（垃圾问题感知、垃圾循环知识、垃圾责任意识、个人消费观念）和人口统计因素（年龄）可以有效地区分循环型消费者和非循环型消费者。这对相关公共政策．尤其是城市垃圾管制政策提供了一定的借鉴和启示。     

基于固废磷化渣的复合型防腐阻锈剂对混凝土性能的影响

为了提高严酷环境下建筑的耐久性,研究了防腐阻锈剂和防腐阻锈混凝土。以三乙醇胺、硝酸铝和Ca(OH)₂为原料,经化学反应,制备新型固体醇胺,再按一定质量分数将固体醇胺、固废磷化渣、石膏和苯甲酸钠混合、球磨,制得复合型防腐阻锈剂,将其掺入基准混凝土中,制得防腐阻锈混凝土,并研究其力学性能和防腐阻锈性能。结果表明：掺复合型防腐阻锈剂的防腐阻锈混凝土,抗压强度和抗折强度显著提高,抗渗等级达P12,碳化深度大幅降低,抗冷热干湿循环和抗冻融性能优异,用含防腐阻锈剂的海水混合液浸泡钢筋2年,钢筋无腐蚀行为。用复合型防腐阻锈剂制备的防腐阻锈混凝土能有效延缓建筑混凝土的腐蚀进程。利用固废磷化渣制备防腐阻锈剂,变废为宝,可为新型防腐阻锈剂的开发提供借鉴。     

Does Entry Size Matter? The Impact of the Life Cycle and Technology on Firm Survival

A wave of empirical studies has recently emerged showing that smaller-scale entry is confronted with a lower likelihood of survival than their larger counterparts. The purpose of this paper is to examine whether the relationship between size of a firm when entering an industry and the likelihood of survival holds under different technological conditions and across the different stages of the industry life cycle. The empirical evidence suggests that the relationship between firm size and the likelihood of survival is shaped by technology and the stage of the industry life cycle. While the likelihood of survival confronting small entrants is generally less than that confronting their larger counterparts, the relationship does not hold for mature stages of the product life cycle, or in technologically intensive products. In mature industries that are still technologically intensive, entry may be less about radical innovation and possibly more about filling strategic niches, thus negating the impact of entry size on the likelihood of survival.     

建设项目环境绩效评价指标体系的构建

环境绩效评价的引入和推广使建筑业越来越关注其自身活动对环境的影响。迄今,学术界对环境绩效评价的研究成果显著,不仅基于自然环境、社会环境、经济环境的三角关系形成可持续性评价的研究领域,还基于项目全生命周期管理创立了全生命周期评价的理论体系。基于文献综述和问卷调查,设计出一套适用于建设项目的环境绩效指标,并分析各指标的数据可获得性、重要性及应受关注度,为国内建设项目更加科学地进行环境绩效评价提供了理论支持。     

Implementation of reverse logistics as a sustainable tool for raw material purchasing in developing countries: The case of Venezuela

This study aims to analyze and understand the benefits that acquiring raw materials through the application of reverse logistics can generate, especially in developing countries. An empirical study has been carried out in the handmade sector of five municipalities in the state of Mérida, Venezuela, into the contingency factors of reverse logistics (information and communication systems, total ownership costs and life cycle of products), as well as the effect of uncertainty. A case study methodology was used to test the effect of the independent variables on the “raw materials purchasing” variable, and involved the technique of stepwise multiple regression. The results reveal that the preference for purchasing raw materials through reverse logistics is mainly determined by the “uncertainty” variable, contingency factors of “information and communication systems” and the “life cycle of products”. According to the results, firms in the handmade sector should implement an information system and be in constant communication with their customers, who play a dual role as buyers of their products and as input suppliers, therefore, greater contact can help reduce uncertainty. Handmade sector workers make products with a long average life cycle and, therefore, with greater chances of being reused, restored, repaired and to finally be subjected to recycling. National and local authorities should encourage the application of reverse logistics in other productive sectors, such as manufacturing, agriculture, services, as it can reduce the problem of acquisition of production inputs and mitigate environmental damage caused by the production of raw materials.