Probabilistic method and its application for evaluating carbonation life of newly-built concrete structures

In order to evaluate the carbonation life of newly-built concrete structures,two kinds of nondestructive methods are adopted to test the thickness of the concrete cover and the ultrasonic velocity of two newly-built tunnel structures.Simultaneously a probabilistic method is proposed based on the relationship between the accelerated carbonation rate and the ultrasonic velocity.This proposed method is applied to evaluate the carbonation related lives of two newly-built tunnels and the results indicate that even under nearly the same environment and CO2 combining conditions,there exits a big difference in the probabilistic carbonation lives between the two tunnels;i.e.,the probabilistic lives of Tunnel A and Tunnel B are 94.0% and 82.3% and the corresponding maximum discrepancies are 11.6% and 27.0%,respectively.Thus,it can be concluded that the scattered quality of the concrete cover is attributed to the differences in construction technique,which eventually leads to the diversity in the evaluated probabilistic carbonation lives of the two tunnels.

Estimation of Building’s Life Cycle Carbon Emissions Based on Life Cycle Assessment and Building Information Modeling: A Case Study of a Hospital Building in China

Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans. Researchers have made numerous efforts to accurately calculate emissions to reduce the life cycle carbon emissions of residential buildings. Nevertheless, there are still difficulties in quickly estimating carbon emissions in the design stage without specific data. To fill this gap, the study, based on Life Cycle Assessment (LCA) and Building Information Modeling (BIM), proposed a quick method for estimating Building’s Life Cycle Carbon Emissions (BLCCE). Taking a hospital building in Chuzhou City, Anhui Province, China as an example, it tested its possibility to estimate BLCCE. The results manifested that: 1) the BLCCE of the project is 40,083.56 tCO2-eq, and the carbon emissions per square meter per year are 119.91 kgCO2-eq/(m2·y);2) the stage of construction, operational and demolition account for 7.90%, 91.31%, and 0.79% of BLCCE, respectively;3) the annual carbon emissions per square meter of hospital are apparently higher than that of villa, residence, and office building, due to larger service population, longer daily operation time, and stricter patient comfort requirements. Considering the lack of BLCCE research in Chinese hospitals, this case study will provide a valuable reference for the estimated BLCCE of hospital building.

Durability Analysis and Carbonation Life Prediction of Shajiang River Bridge

The shajiang river bridge on the appearance test, concrete rebound detection, concrete cover depth detection, concrete carbonation depth detection, concrete chlorine ion content detection, and the detection results in statistics and analysis. Based on the bridge of the service the atmospheric environment parameters and testing data, the paper calculates and analyzes the main stress components the carbonation bridge reliability index and remaining life of carbide, assessing the bridge for the service life and reinforcement maintenance and offer the scientific basis.

High energy density performance of hydrothermally produced hydrous ruthenium oxide/multiwalled carbon nanotubes composite: Design of an asymmetric supercapacitor with excellent cycle life

Hydrous ruthenium oxide(h-Ru O) nanoparticles and its composite with multiwalled carbon nanotubes(h-Ru O/MWCNT) were synthesized by a simple hydrothermal method and proved to have potential application as hybrid supercapacitor material.The h-Ru Oand h-Ru O/MWCNT were characterized for their physico-chemical properties by PXRD,BET surface area,Raman,SEM-EDS and TEM techniques.The electrochemical performance of the materials were investigated,specific capacitance(Cs) of h-Ru Oand hRu O/MWCNT estimated by their cyclic voltammetric studies were found to be 604 and 1585 F/g respectively at a scan rate of 2 m V/s in the potential range 0–1.2 V.Further,this value was found to be nearly three times higher than that of pure h-Ru O.An asymmetric supercapacitor(AS) device was fabricated by employing h-Ru O/MWCNT as the positive electrode and activated carbon as the negative electrode.The device exhibited Cs of 61.8 F/g at a scan rate of 2 m V/s.Further,the device showed excellent long term stability for 20,000 cycles with 88% capacitance retention at a high current density of 25 A/g.

Service Life Prediction of Lining Concrete of Subsea Tunnel under Combined Compressive Load and Carbonation

Qingdao Jiaozhou Bay subsea tunnel is the second self-built tunnel in China with the designed service life over 100 years.The durability of lining concrete are one of an important factors to determinate the service life of tunnel.Considering the main environmental loads and mechanical loads of subsea tunnel,the durability properties of lining concrete under combined action of compressive load and carbonation has been studied through the critical compressive load test,accelerated carbonation test,natural carbonation test and capillary suction test.The tests results show that critical compressive load apparently accelerates the carbonation and deteriorates the anti-permeability of concrete.Under the combined action of critical compressive load and carbonation,the durability of lining concrete decreases.Based on the carbonization life criteria and research results,for the high-performance concrete with proposed mix ratio,the predicted service life of lining concrete for Jiaozhou bay subsea tunnel is about 80 years which fails to reach the required service life.It is necessary to adopt other measurements simultaneously to improve the durability of lining concrete.

Research on whole life cycle carbon emission model of typical buildings

Based on the theory of life cycle assessment(LCA),this article analyzes the influence factors on carbon emissions from residential buildings.In the article,the life cycle of residential buildings has been divided into five stages:building materials production period,construction period,operation and maintenance period,demolition period,and solid waste recycle and disposal period.Based on this definition,the authors provide a theoretical model to calculate carbon emissions of residential building life cycle.In particular,the factor of human activities was introduced in the calculation of carbon emissions from the buildings.Furthermore,the authors put forward a model for calculation with the unit of carbon emissions for per-capita living space.

不同负极材料对LiFePO_(4)高功率储能器件循环性能的影响

磷酸铁锂(LiFePO_(4),LFP)以低成本、高安全性、长循环寿命等优点在近些年来备受关注,然而市场上常见的LFP储能器件在0.1~2 C倍率的循环寿命为2000次左右。为了进一步开发高功率、长寿命的LFP储能器件,本文设计了容量为9 Ah的不同负极材料(硬碳/软碳/石墨)软包储能器件。对4 C大倍率循环性能进行探究,发现4000次循环后,硬碳和软碳用作负极的储能器件的容量保持率分别为83.0%、78.9%,优于石墨(51.6%)。通过XRD、EIS、容量增量法和电压微分法等手段进行分析,发现接触内阻和SEI膜内阻增加,以及结构变化造成负极中锂离子的消耗是容量衰减的主要原因。进一步探究石墨用作负极时循环寿命差的原因,发现石墨用作负极时库仑效率较低,工作温度较高,dQ/dV峰值在循环过程中发生更大的位移,峰强的降幅也较大。由于石墨的层间距为0.335 nm,小于软碳(0.360 nm)和硬碳(0.395 nm),在反复脱嵌锂过程中石墨更易发生结构变化,造成体积膨胀,因此循环后接触电阻和SEI膜电阻增长幅度较高,锂离子扩散动力学也更差。与石墨相比,硬碳和软碳用作大倍率LFP储能器件的负极活性物质时具有更长的循环寿命。

基于实际项目的绿色建筑全寿命周期碳排放水平分析

建筑碳排放计算已成为硬性要求,绿色建筑作为建筑行业重要部分及关键碳减排路径之一,对其碳排放情况进行分析具有重要意义。本文以获得绿色建筑标识的59个公共建筑和26个居住建筑实际项目为研究对象,采用全寿命周期碳排放分析方法,归纳、统计不同阶段、不同星级、不同功能绿色建筑的碳排放水平,并根据绿色建筑全寿命周期碳排放特征,提出了绿色建筑设计、建造与运维管理减碳措施建议,以期推动规模化推广绿色建筑、实现全过程协同降碳。

A Review of the Life Cycle Analysis for Plastic Waste Pyrolysis

Pyrolysis is a rapidly expanding chemical-based recyclable method that complements physical recycling. It avoids improper disposal of post-consumer polymers and mitigates the ecological problems linked to the production of new plastic. Nevertheless, while there is a consensus that pyrolysis might be a crucial technology in the years to come, more discussions are needed to address the challenges related to scaling up, the long-term sustainability of the process, and additional variables essential to the advancement of the green economy. Herein, it emphasizes knowledge gaps and methodological issues in current Life Cycle Assessment (LCA), underlining the need for standardized techniques and updated data to support robust decision-making for adopting pyrolysis technologies in waste management strategies. For this purpose, this study reviews the LCAs of pyrolytic processes, encompassing the complete life cycle, from feedstock collection to end-product distribution, including elements such as energy consumption, greenhouse gas emissions, and waste creation. Hence, we evaluate diverse pyrolysis processes, including slow, rapid, and catalytic pyrolysis, emphasizing their distinct efficiency and environmental footprints. Furthermore, we evaluate the impact of feedstock composition, process parameters, and scale of operation on the overall sustainability of pyrolysis-based plastic waste treatment by integrating results from current literature and identifying essential research needs. Therefore, this paper argues that existing LCA studies need more coherence and accuracy. It follows a thorough evaluation of previous research and suggests new insights into methodologies and restrictions.

CO_(2)-ESGR 技术全生命周期碳排放分析

在页岩气井开采后期,将CO_(2)注入页岩气藏可在提高页岩气采收率的同时实现CO_(2)地质封存(CO_(2)-ESGR),但目前对于CO_(2)-ESGR技术减碳潜力尚缺乏从全生命周期角度进行的研究。为此,分别以重庆市双槐电厂、涪陵页岩气田作为CO_(2)源和汇,采用全生命周期评价方法,建立了CO_(2)-ESGR技术全过程CO_(2)排放量核算模型,进而基于多场耦合作用下CO_(2)、CH_(4)渗流数学模型得到了CO_(2)封存量及页岩气产量,并系统核算了CO_(2)-ESGR全过程CO_(2)排放量,分析了CO_(2)注入压力、页岩中CO_(2)相对CH_(4)的吸附选择性系数(αCO_(2)/CH_(4))等参数对CO_(2)净减排量的影响。研究结果表明:①CO_(2)注入压力和αCO_(2)/CH_(4)对于CO_(2)净减排量具有重要影响,αCO_(2)/CH_(4)越大,CO_(2)净减排量越大,CO_(2)注入压力增加,CH_(4)累计产量、CO_(2)封存量、CO_(2)净减排量均越大,不同CO_(2)注入压力条件下CO_(2)净减排量为0.85~2.06 tCO_(2)/tCH_(4),而在不同αCO_(2)/CH_(4)条件下可达1.59~5.45 tCO_(2)/tCH_(4);②CO_(2)捕集、运输、注入环节是影响CO_(2)-ESGR技术全生命周期CO_(2)净减排量的关键因素,需要考虑不同行业组合、源汇匹配情况对CO_(2)净减排量的影响,进而对全流程CCUS工程实施方案进行优化。结论认为:①该CO_(2)-ESGR工程CO_(2)封存量大于CO_(2)捕集、运输、注入及页岩气生产与利用环节的CO_(2)总排放量,可实现CO_(2)-ESGR全过程CO_(2)负排放,说明CO_(2)-ESGR是实现中国“碳中和”的重要技术路径之一;②下一步研究应综合考虑CO_(2)注入时机、压力、速率等工程参数以及页岩气储层条件等地质因素对于CO_(2)封存量和净减排量的影响,对CO_(2)-ESGR系统进行优化。

基于碳排放因子法的建筑涂料碳足迹计算分析

基于碳排放因子法,以建筑涂料为研究对象,根据生命周期评价法对其从“摇篮到大门”的部分阶段碳足迹进行了详细的计算和分析。通过综合评估从原材料获取及运输、生产制造等各个环节的碳排放情况,揭示了建筑涂料在“摇篮到大门”阶段碳足迹特征和影响因素。研究发现,建筑涂料的碳足迹主要集中在原材料获取和产品生产阶段,特别是与原材料的采集和加工、生产过程中的能源消耗密切相关。全面分析了建筑涂料生产过程产生碳排放的主要阶段和原因,可以为减少建筑涂料碳足迹提供理论依据和技术指导。

Application of Life-Cycle Assessment for the Study of Carbon and Water Footprints of the 16.5 MWe Wind Farm in Villonaco, Loja, Ecuador

Wind technology is considered to be among the most promising types of renewable energy sources, and due to high oil prices and growing concerns about climate change and energy security, it has been the subject of extensive considerations in recent years, including questions related to the relative sustainability of electricity production when the manufacturing, assembly, transportation and dismantling processes of these facilities are taken into account. The present article evaluates the environmental impacts, carbon emissions and water consumption, derived from the production of electric energy of the Villonaco wind farm, located in Loja, Ecuador, during its entire life cycle, using the Life Cycle Analysis for this purpose. Finally, it is concluded that wind energy has greater environmental advantages since it has lower values of carbon and water footprints than other energy sources. Additionally, with the techniques Cumulative Energy Demand and Energy Return on Investment, sustainability in the production of electricity from wind power in Ecuador is demonstrated;and, that due to issues of vulnerability to climate change, the diversification of its energy mix is essential considering the inclusion of non-conventional renewable sources such as solar or wind, this being the only way to reduce both the carbon footprint and the water from the energy supply.

园路铺装碳排放的生命周期评价

[目的]园林工程建造阶段是风景园林项目中碳足迹比重最大的部分,而园路铺装又是工程建造碳排放最多的分项。园路铺装的材料生产、工程建造及运输、使用维护以及材料回收再利用,各阶段都产生了大量的碳排放。评估不同面层类型园路铺装的生命周期碳排放量,可以为园林工程低碳减排研究提供理论依据。[方法]以25种常见的园路铺装为例,构建园路铺装生命周期碳排放计算模型,厘清并计算各种园路铺装的生命周期碳排放量,并将结果进行归一化处理和评价。[结果]发现25种园路铺装中,生命周期内碳排放量最高的3种园路铺装是胶粘石路面、防腐木路面、石灰岩路面;碳排放量最低的3种园路铺装是混凝土路面、再生骨料混凝土路面和压膜艺术地坪。而将碳排放量进行单位面积和年均处理后,碳排放量最高的3种园路铺装是胶粘石路面、透水混凝土砖路面、砂基透水砖路面;排放量最低的3种园路铺装是再生骨料混凝土路面、压膜艺术地坪和混凝土路面。[结论]将碳排放量计算结果和具体实践结合进行分析评价,得出园路铺装碳排放量生命周期评价结论:生命周期年均碳排放的高低与面层材料耐久性有较大的关系;混凝土作为园路铺装的基础性结构,在其上增加其他面层的做法会增加碳排放量;以高强、薄型材料作为园路铺装面层材料的路面,生命周期内所产生的碳排放较低;面层材料的寿命对年均碳排放量的影响高于其他因素。

建筑工程碳中和监测管理平台构建研究

在双碳目标下,为解决建筑工程全生命周期内各阶段碳排放量连续监测和计算问题,本文在确定碳排放计算方法、模型的基础上,构建建筑工程碳中和监测管理平台,通过剖析平台功能目标、碳排放计算系统、平台架构设计,实现平台碳排放自动计算、大数据监测统计、低碳智能分析、数据信息管理等功能,希望为建筑工程碳排放量监测和减碳管理提供参考。

生命周期评价方法在制革领域的应用研究现状分析

皮革工业是我国具有国际竞争优势的传统轻工支柱产业,其绿色低碳转型升级已是必然趋势。生命周期评价(Life Cycle Assessment,LCA)作为一种系统性、综合性的评价方法,可用于量化制革过程的资源环境影响。文章简要回顾了LCA方法的发展历程、标准流程与理论框架,重点总结了LCA方法在制革领域应用的研究现状及其对制革减污降碳的指导作用,以及现存的问题和解决方案。结合作者在皮革产品碳足迹核算标准方法研制与皮革化学品碳排因子数据库构建方面的研究与实践,核算形成皮革产品碳足迹数据库,并提出构建制革工艺LCA环境影响预测模型,希望赋能绿色低碳制革生产和皮革行业高质量发展。

不同栽培技术与品种对华南籼稻产量、肥料利用率和间接碳足迹的影响

协同实现水稻高产和碳减排对维护国家粮食自给和实现碳达峰碳中和意义重大。为定量分析华南地区水稻生产碳足迹及构成特征,明确栽培技术对水稻产量及碳足迹的影响,本研究在广东省4个典型的水稻产区开展田间试验,利用生命周期评价法分析不同栽培技术模式的水稻产量、肥料利用率和间接碳足迹及其构成。结果表明,广东省籼稻生产单位面积碳足迹为1235.3~1487.7 kg CO_(2)-eq/hm^(2),单位产量碳足迹为0.12~0.31 kg CO_(2)-eq/kg;栽培技术对水稻产量、化肥利用效率、灌溉次数和单位产量碳足迹有显著影响。与常规栽培技术相比,低碳高产栽培技术显著减少氮肥用量,并提高了水稻产量,栽培技术和品种之间无显著交互作用。相同技术模式下,单位产量间接碳足迹与产量呈极显著负相关,表明在相同种植条件下选用高产水稻品种能有效降低单位产量碳足迹。示范区的多点试验表明,与常规栽培技术相比,低碳高产栽培技术水稻产量增加3.67%~21.62%,氮肥偏生产力提高21.68%~60.81%,每季平均减少灌溉次数4次,单位面积碳足迹和单位产量碳足迹均值分别减少6.11%和16.19%。柴油和氮肥是影响间接碳足迹的关键因子,两者碳排放分别占总间接排放量49.65%~52.88%和30.62%~34.70%。平均每减少1 kg氮肥,碳足迹降低2.49 kg CO_(2)-eq/hm^(2)。水稻单位产量间接碳足迹与氮肥偏生产力呈极显著负相关,表明提高单位产量和氮肥利用率能有效减少水稻单产间接碳足迹。综上表明,华南地区水稻生产可通过选用高产水稻品种,结合水肥优化栽培技术降低氮肥和灌溉水投入,提高水稻产量和氮肥利用率,减少单位面积碳足迹和单位产量碳足迹,实现高产与低碳排的协同。

Low-carbon Living Environment Design

Based on the review of the influence of human activity on global environment,and recognition of current climate warming,it is considered that human activity is the primary reason and climate change has caused serious global environmental problems and threatened human's survival and development.After the introduction of low carbon and conclusion of the main contents and development of researches,it has emphasized that low-carbon urban living mode is an important component of low-carbon urban planning.In view of the situation of China,the main content of low-carbon urban living mode has been illustrated from the perspective of low-carbon life behavior,low-carbon life consumption and carbon budget life mode.On this basis,the purpose and significance of low-carbon living environment design,design principles and requirements,low-carbon life measures have been analyzed.

混凝土全寿命周期固碳技术研究进展

混凝土制备产生的碳排放占建筑业碳排放的28%,固碳技术成为实现“双碳”目标的关键。混凝土固碳技术是指利用CO_(2)与混凝土孔溶液中碱金属离子(如Ca^(2+)和Mg^(2+))或水化产物的碳化反应生成稳定的碳酸盐来实现CO_(2)的封存。碳化反应会影响孔溶液、孔结构和水化产物的特性,进而影响混凝土的力学和耐久性能。本文围绕混凝土全寿命周期(拌合、养护、服役、二次利用),对混凝土固碳技术进行总结,对不同固碳技术的碳化机理、技术特点和固碳潜力进行了论述。拌合阶段注入CO_(2)可促使混凝土主动碳化,但会消耗能量并产生新的碳排放。碳化养护可提高混凝土早期强度,但致密的碳化产物限制了碳化的进一步发展。服役阶段的碳化无需人为干预,固碳潜力大,但其碳化速率较低。二次利用阶段的碳化不仅可实现CO_(2)封存,还可改善再生骨料的品质。对现有技术进行优化、引入新材料和新结构形式有助于提升全寿命周期混凝土的CO_(2)封存效率。

重庆市烟草-玉米轮作系统碳足迹研究——基于生命周期评价

为明确烟玉(烤烟-玉米)轮作系统碳足迹,本研究基于农户调研数据采用生命周期评价法核算重庆市烟玉轮作系统(研究边界为烟草育苗至烘烤,玉米播种至收获)碳足迹,分析其构成及影响因素,探究种植规模和农户受教育水平与轮作系统碳足迹关系。结果表明:重庆市烟玉轮作系统单位面积碳足迹、单位产量碳足迹、单位产值碳足迹分别为16255.06 kg·hm^(-2)、1.89 kg·kg^(-1)、0.25 kg·元^(-1);烟草和玉米生产单位面积碳足迹分别为17870.71、2618.13 kg·hm^(-2),在轮作系统中贡献占比分别为87.2%、12.8%;烘烤烟叶能源消耗、农膜、肥料是重庆市烟玉轮作碳足迹主要贡献源,占比分别为72.6%、13.6%和8.7%;烘烤用煤和烘烤用电与烟玉轮作系统碳足迹呈显著正相关,种植规模和调研农户受教育水平与碳足迹呈负相关。加快取缔煤烤房进程,实行废旧农膜统一回收,施用缓释肥,与甘薯、大豆等需氮量少的作物轮作是重庆市烟玉轮作系统实现减排和发展低碳农业的关键途径,合并地块适当发展规模化种植、增加低碳知识普及、建立监督奖励机制推动低碳措施实行是减少农户碳足迹的重要举措。

城市公园绿地碳汇能力影响因素的网状荟萃(Meta)分析

[目的]城市公园绿地为人类提供与健康福祉密切相关的多种生态系统服务,具备生态、社会、经济多重效益,其碳汇能力受多个影响因素控制。综合评估多个因素对城市公园绿地碳汇能力的影响,以此探讨低碳城市公园设计策略的最优解。[方法]以“碳汇”“公园”等为关键词进行文献检索,使用网状荟萃(Meta)分析对城市公园绿地碳汇能力的不同影响因素进行系统性定量评估,并根据其影响大小进行分类统计。通过基于网络证据图的影响因素重要性评估、基于联赛表的相对影响能力分析、基于累积排序概率曲线下面积(surface under the cumulative ranking curves,SUCRA)图的综合影响能力分析,综合评估不同影响因素对城市公园绿地碳汇能力的实际作用,并结合亚组分析和漏斗图评估研究样本的异质性、误差及偏倚。[结果]共检索952篇文献,纳入50篇有效文献,提取34个城市公园绿地碳汇能力的关键影响因素,划分为设计形态、生境组成、种植方式、管护形式、外部环境五大聚类。其中,设计形态和管护形式对于提升城市公园绿地碳汇能力效果稳定,适用性较强,是提升碳汇能力的基础因素;生境组成和种植方式在特定场景下提升碳汇能力效果显著,但受场地特征限制;外部环境对城市公园绿地碳汇能力的直接影响较弱。[结论]城市公园绿地碳汇能力受多种因素共同作用,在以碳汇为导向的设计方案中,应优先考虑优化设计形态和管护形式,根据场地实际条件灵活调配不同的生境组成和种植方式,并适当考虑外部环境的影响。