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Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 473-486 doi: 10.1007/s11709-020-0608-5

摘要： Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted. However, these previous studies did not consider the effects of climate change, such as acceleration in the deterioration of durability, on mixture design. This study presents a procedure for the optimal mixture design of ternary blended concrete considering climate change and durability. First, the costs of CO emissions and material are calculated based on the concrete mixture and unit prices. Total cost is equal to the sum of material cost and CO emissions cost, and is set as the objective function of the optimization. Second, strength, slump, carbonation, and chloride ingress models are used to evaluate concrete properties. The effect of different climate change scenarios on carbonation and chloride ingress is considered. A genetic algorithm is used to find the optimal mixture considering various constraints. Third, illustrative examples are shown for mixture design of ternary blended concrete. The analysis results show that for ternary blended concrete exposed to an atmospheric environment, a rich mix is necessary to meet the challenge of climate change, and for ternary blended concrete exposed to a marine environment, the impact of climate change on mixture design is marginal.

关键词： ternary blended concrete     climate change     optimal mixture design     carbonation     chloride ingress    

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Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

WU Yuching, ZHU Cimian

《结构与土木工程前沿（英文）》 2007年 第1卷 第4期   页码 464-473 doi: 10.1007/s11709-007-0063-6

摘要： The iterative finite element model, in which an element is used to represent a single particle, is generated to analyze the global behavior of multiple-material aggregates of materially nonlinear viscoplastic particles. The genera

关键词： nonlinear viscoplastic     iterative     behavior     multiple-material    

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Study on combustion characteristics of blended coals

LI Yonghua, WANG Chunbo, CHEN Hongwei

《能源前沿（英文）》 2007年 第1卷 第1期   页码 96-100 doi: 10.1007/s11708-007-0010-1

摘要： Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons. So it is of great necessity to investigate the combustion of blended coals. Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system, characteristics such as burnout, slag, and pollution of some blended coals were investigated. The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced. The results show that the blending of coal has some effect on NO but there is no obvious rule. SO emission can be reduced by blending low sulfur coal.

关键词： combustion     capacity     variety     blended     burnout    

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Experimental investigation on mechanical properties of binary and ternary blended pervious concrete

Rekha SINGH, Sanjay GOEL

《结构与土木工程前沿（英文）》 2020年 第14卷 第1期   页码 229-240 doi: 10.1007/s11709-019-0597-4

摘要： The purpose of the investigation was to study the effect of binary and ternary blends of cement on the mechanical properties of pervious concrete (PC) specimen through destructive (DT) and non-destructive testing (NDT). Various combinations of fly ash (FA), limestone powder (LP), metakaolin (MK), and silica fume (SF) as mineral admixtures have been investigated to partially replace the cement up to 30% by weight in PC. Standard cube specimens of size 150 mm × 150 mm × 150 mm of binary and ternary blends of mineral admixture of pervious concrete were prepared to conduct standard compressive strength test and split tensile test at 7 and 28 days of curing. The ultrasonic pulse velocity (UPV) test and Rebound Hammer test were used as a non-destructive testing tool to substantiate the robustness of PC and to determine the approximate mechanical properties where other destructive testing tools are not feasible in case of in-place pervious pavements. Overall the pervious concrete made with LP based ternary blends (PLM and PLS) were found to perform better than FA based ternary blends (PFM and PFS) and control mix (PC) in destructive and non-destructive testing.

关键词： mineral admixture     ternary     compressive strength     split tensile strength     pervious concrete     ultrasonic pulse velocity    

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/i> and H2S formation in the reductive zone of air-staged combustion of pulverized blended

Jinzhi CAI, Dan LI, Denggao CHEN, Zhenshan LI

《能源前沿（英文）》 2021年 第15卷 第1期   页码 4-13 doi: 10.1007/s11708-020-0804-y

摘要： Low NO combustion of blended coals is widely used in coal-fired boilers in China to control NO emission; thus, it is necessary to understand the formation mechanism of NO and H S during the combustion of blended coals. This paper focused on the investigation of reductive gases in the formation of NO and H S in the reductive zone of blended coals during combustion. Experiments with Zhundong (ZD) and Commercial (GE) coal and their blends with different mixing ratios were conducted in a drop tube furnace at 1200°C–1400°C with an excessive air ratio of 0.6–1.2. The coal conversion and formation characteristics of CO, H S, and NO in the fuel-rich zone were carefully studied under different experimental conditions for different blend ratios. Blending ZD into GE was found to increase not only the coal conversion but also the concentrations of CO and H S as NO reduction accelerated. Both the CO and H S concentrations inblended coal combustion increase with an increase in the combustion temperature and a decrease in the excessive air ratio. Based on accumulated experimental data, one interesting finding was that NO and H S from blended coal combustion were almost directly dependent on the CO concentration, and the CO concentration of the blended coal combustion depended on the single char gasification conversion.Thus, CO, NO , and H S formation characteristics from blended coal combustion can be well predicted by single char gasification kinetics.

关键词： blended coal combustion     NOx formation     H2S formation     air staged combustion    

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strength and durability of self-compacting concrete modified with controlled-burnt sugarcane bagasse ash-blended

《结构与土木工程前沿（英文）》 2022年 第16卷 第2期   页码 161-174 doi: 10.1007/s11709-021-0796-7

摘要： In sugar industries, the growing amount of sugarcane bagasse ash (SBA), a byproduct released after burning bagasse for producing electricity, is currently causing environmental pollution. The residual ash displays a pozzolanic potential; and hence, it has potential as a cement addictive. This study focuses on enhancing suitability of SBA through incorporating ground blast furnace slag (BFS) in manufacturing self-compacting concretes (SCCs). For this purpose, SBA was processed by burning at 700 °C for 1 h, before being ground to the cement fineness of 4010 cm2/g. SCC mixtures were prepared by changing the proportions of SBA and BFS (i.e., 10%, 20%, and 30%) in blended systems; and their performance was investigated. Test results showed that the presence of amorphous silica was detected for the processed SBA, revealing that the strength activity index was above 80%. The compressive strength of SCC containing SBA (without BFS) could reach 98%−127% of that of the control; combination of SBA and 30% BFS gets a similar strength to the control after 28 d. Regarding durability, the 10%SBA + 30%BFS mix exhibited the lowest risk of corrosion. Moreover, the joint use of SBA and BFS enhanced significantly the SCC’s sulfate resistance. Finally, a hyperbolic formula for interpolating the compressive strength of the SBA-based SCC was proposed and validated with error range estimated within ±10%.

关键词： sugarcane bagasse ash     self-compacting concrete     compressive strength     sulfate resistance     water absorption     strength formula    

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Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with

Baicang Liu,Chen Chen,Pingju Zhao,Tong Li,Caihong Liu,Qingyuan Wang,Yongsheng Chen,John Crittenden

《化学科学与工程前沿（英文）》 2016年 第10卷 第4期   页码 562-574 doi: 10.1007/s11705-016-1588-9

摘要： To advance commercial application of forward osmosis (FO), we investigated the effects of two additives on the performance of polysulfone (PSf) based FO membranes: one is poly(ethylene glycol) (PEG), and another is PSf grafted with PEG methyl ether methacrylate (PSf-g-PEGMA). PSf blended with PEG or PSf-g-PEGMA was used to form a substrate layer, and then polyamide was formed on a support layer by interfacial polymerization. In this study, NaCl (1 mol?L ) and deionized water were used as the draw solution and the feed solution, respectively. With the increase of PEG content from 0 to 15 wt-%, FO water flux declined by 23.4% to 59.3% compared to a PSf TFC FO membrane. With the increase of PSf-g-PEGMA from 0 to 15 wt-%, the membrane flux showed almost no change at first and then declined by about 52.0% and 50.4%. The PSf with 5 wt-% PSf-g-PEGMA FO membrane showed a higher pure water flux of 8.74 L?m ?h than the commercial HTI membranes (6–8 L?m ?h ) under the FO mode. Our study suggests that hydrophobic interface is very important for the formation of polyamide, and a small amount of PSf-g-PEGMA can maintain a good condition for the formation of polyamide and reduce internal concentration polarization.

关键词： thin-film composite     forward osmosis     amphiphilic copolymer     interfacial polymerization     poly(ethylene glycol)    

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PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times

Shuai Wang, Tong Li, Chen Chen, Baicang Liu, John C. Crittenden

《环境科学与工程前沿（英文）》 2018年 第12卷 第2期 doi: 10.1007/s11783-017-0980-0

摘要： Polyvinylidene fluoride grafted with poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) was synthesized using atomic transfer radical polymerization (ATRP) at different reaction times (9 h, 19 h, and 29 h). The corresponding conversion rates were 10%, 20% and 30%, respectively. PVDF was blended with the copolymer mixture containing PVDF-g-PEGMA, solvent and residual PEGMA under different reaction times. In this study, we explored the effect of the copolymer mixture additives with different synthesis times on cast membrane performance. Increasing the reaction time of PVDF-g-PEGMA causes more PVDF-g-PEGMA and less residual PEGMA to be found in the casting solution. Incremental PVDF-g-PEGMA can dramatically increase the viscosity of the casting solution. An overly high viscosity led to a delayed phase inversion, thus hindering PEGMA segments in PVDF-g-PEGMA from migrating to the membrane surface. However, more residual PEGMA contributed to helping more PEGMA segments migrate to the membrane surface. The pure water fluxes of the blended membrane with reaction times of 9 h, 19 h, and 29 h are 5445 L·m ·h , 1068 L·m ·h and 1179 L·m ·h , respectively, at 0.07 MPa. Delayed phase inversion can form smaller surface pore size distributions, thus decreasing the water flux for the membranes with PVDF-g-PEGMA at 19 h and 29 h. Therefore, we can control the membrane pore size distribution by decreasing the reaction time of PVDF-g-PEGMA to obtain a better flux performance. The membrane with PVDF-g-PEGMA at 19 h exhibits the best foulant rejection and cleaning recovery due to its narrow pore size distribution and high surface oxygen content.

关键词： Polyvinylidene fluoride ultrafiltration membrane     Amphiphilic copolymer     Blended modification     High flux     Atomic transfer radical polymerization    

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标题 作者 时间 类型 操作

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

期刊论文

Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

WU Yuching, ZHU Cimian

期刊论文

Study on combustion characteristics of blended coals

LI Yonghua, WANG Chunbo, CHEN Hongwei

期刊论文

Experimental investigation on mechanical properties of binary and ternary blended pervious concrete

Rekha SINGH, Sanjay GOEL

期刊论文

/i> and H2S formation in the reductive zone of air-staged combustion of pulverized blended

Jinzhi CAI, Dan LI, Denggao CHEN, Zhenshan LI

期刊论文

strength and durability of self-compacting concrete modified with controlled-burnt sugarcane bagasse ash-blended

期刊论文

Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with

Baicang Liu,Chen Chen,Pingju Zhao,Tong Li,Caihong Liu,Qingyuan Wang,Yongsheng Chen,John Crittenden

期刊论文

PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times

Shuai Wang, Tong Li, Chen Chen, Baicang Liu, John C. Crittenden

期刊论文