摘要：
It has been reported that iron tailing powder (ITP) has the potential to partially replace cement to prepare ultra-high-performance concrete (UHPC). However, the reactivity of ITP particles in concrete largely depends on the curing method. This study investigates the effects of curing conditions on the mechanical and microstructural properties of UHPC containing ITP. To achieve this objective, three research tasks are conducted, including (1) preparing seven concrete formulations by introducing ITP; (2) characterizing their mechanical performance under different curing regimes; and (3) analyzing their microstructure by XRD patterns, FTIR analysis, and SEM observation. The experimental results show that there is an optimum ITP dosage (15%) for their application. The concrete with 15% ITP under standard curing obtains 94.3 MPa at 7 days, their early-age strength could be even further increased by similar to 30% (warm-water curing) and similar to 35% (steamed curing). The steam curing regime stimulates the activity of ITP and refines the microstructure. This study demonstrates the potential of replacing Portland cement with ITP in UHPC production.
关键词：
energy consumption;graphene oxide;nanocomposite bricks;self-heating
摘要：
In cold climate regions, the energy associated with indoor heating constitutes a large portion of energy consumption. Increasing energy utilization efficiency is critically important for both economic and environmental reasons. Directly converting electrical energy to thermal energy using joule heating construction elements can save energy and investment to the water pipelines which have been extensively used for indoor heating in China. The fired brick has been extensively used to make pavements, walls and other masonry. Taking advantage of the high dispersion quality of graphene oxide (GO) in water, as well as the firing process used to make fired bricks, graphene nanocomposite bricks with excellent electrical properties and improved mechanical performance were prepared in China. The compressive strength of the bricks showed a substantial increase from 3.15 MPa to 7.21 MPa when GO concentration was 0.1 wt.%. Through applying 5 volts of electrical field within 5 minutes, the nanocomposites can be heated from room temperature to 60 degrees C, 110 degrees C and 160 degrees C for the nanocomposite bricks with graphene concentration of 3 wt.%, 4 wt.% and 5 wt.%, respectively, due to the extremely low percolation threshold (similar to 0.5 wt.%) and high conductivity (10 Omega<bold>cm at </bold>1 wt.%). The sheets were connected more tightly when the GO content was increased. The thermal efficiency can reach up to 88% based on the applied voltage, measured resistance and temperature rise curves.
期刊：
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY,2019年19(8):4465-4473 ISSN：1533-4880
通讯作者：
Shi, Xianming
作者机构：
[Gong, Jing; Li, Zhipeng; Zhang, Rongtang] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Hubei, Peoples R China.;[Gong, Jing] Wuchang Univ Technol, Coll Urban Construct, Wuhan 430223, Hubei, Peoples R China.;[Li, Jianfen] Wuhan Polytech Univ, Sch Chem Engn & Environm, Wuhan 430023, Hubei, Peoples R China.;[Shi, Xianming] Washington State Univ, Dept Civil & Environm Engn, Lab Adv & Sustainable Cementitious Mat, Pullman, WA 99164 USA.
通讯机构：
[Shi, Xianming] W;Washington State Univ, Dept Civil & Environm Engn, Lab Adv & Sustainable Cementitious Mat, Pullman, WA 99164 USA.
关键词：
High Volume Fly Ash;Polyethylene Microfiber;Nano-Montmorillonite;Interface;EDX;Microhardness
摘要：
Foamed cement-based materials have attracted much attention as a new type of thermal insulation materials (TIMs) that may offer a sustainable solution to the built environments. This laboratory study explores the combined use of nano-montmorillonite and polyethylene microfiber in foamed paste with high volume fly ash (HVFA) binder. A total of 16 foamed HVFA paste mixtures were fabricated which consisted of 70% Class F fly ash, 30% Portland cement, 2% sodium alpha-olefin sulfonate, 0.38% Na(3)PO(4), and 2% nano-montmorillonite. The dosage and type of polyethylene microfibers (90 mum in diameter) were explored in the present study, with six dosages (0, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% by volume) and three lengths (3 mm, 6 mm, and 9 mm) tested. Based on the experimental results, the highest 28-day rupture strength (1.51 MPa) was achieved with the use of 3-mm long PE microfibers at 0.4 vol.%. Synergistic utilization of nMMT and microfibers exhibited a great influence on the dry density and water absorption of the foamed paste. The SEM micrographs illustrated the multiple mechanisms by which the microfibers serve to reduce shrinkage-induced cracking of the foamed paste. Energy-dispersive X-ray spectroscopy was employed to obtain the contents of Ca, Si, Al, S and mole ratios of Ca/Si, Ca/(Si + Al), S/Ca, and Al/Si in the hardened pastes, which reveal the difference in hydration products near or away from the nMMT-pretreated polyethylene microfibers. The results of microhardness test were also used to elucidate such nano-/micro-synergistic effects, which improved the bonding between microfibers and foamed paste matrix. A mechanism was proposed to explain the role of various admixtures and the balanced performance of such inorganic TIMs.
期刊：
International Journal of Electrochemical Science,2018年13(1):498-513 ISSN：1452-3981
通讯作者：
Shi, Xianming
作者机构：
[Tong, Yangyang; Lit, Zhipeng; Gong, Jing; Shen, Zhang] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Hubei, Peoples R China.;[Shi, Xianming] Washington State Univ, Dept Civil & Environm Engn, Lab Corros Sci & Electrochem Engn, POB 642910, Pullman, WA 99164 USA.
通讯机构：
[Shi, Xianming] W;Washington State Univ, Dept Civil & Environm Engn, Lab Corros Sci & Electrochem Engn, POB 642910, Pullman, WA 99164 USA.
关键词：
Electrical injection of corrosion inhibitor (EICI);Electrochemical chloride extraction (ECE);Finite element modeling;Rebar corrosion;Repair mortar
摘要：
Repair mortar is commonly used to rehabilitate reinforced concrete structures or components that exhibit a relatively high level of distresses. Yet, the repair mortar can be contaminated by salt from its service environment. This work employs a two-dimensional finite element model to investigate the non-stationary transport behavior of ionic species in salt-contaminated and water-saturated repair mortar under an externally applied electric field. The model was experimentally validated and then utilized to evaluate the effectiveness of electrochemical chloride extraction (ECE) with or without electrical injection of corrosion inhibitor (EICI). In the case study, both the ECE alone and the simultaneous ECE+EICI treatment was found effective in decontaminating the zone in front of the steel rebar. In both techniques, the magnitude of current density had a significant effect on removing chloride out of the mortar and increasing the pH of the pore solution near the rebar, whereas the treatment time did not have a significant effect under some scenarios. The injection of the organic corrosion inhibitor significantly slowed down the removal of chloride. Changes in the ionic distribution in the mortar were generally beneficial in reducing the corrosion risk of the steel rebar and thus extending the service life of the repair mortar.
作者机构：
[Gong, Jing; Chen, Huiyu] College of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan, China
通讯机构：
[Chen, H.] C;College of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan, China
关键词：
Building envelope;Energy saving effect;Thermal insulation
摘要：
The development of energy saving building is the inevitable trend of the construction industry since twenty-first century, and energy saving building is not only beneficial to improve the comfort of houses, but also help to build an environment-friendly society. In this paper, the influence of the thermal insulation system of the building envelope on the energy saving effect is mainly analyzed, and the current situation of energy consumption in China and the strategy of building energy saving abroad are introduced. Energy saving building is an urgent requirement for the development of China's architecture. Then, this paper discusses the ways of building energy saving from three aspects: the characteristics and technology of external wall insulation, the current more mature building envelope thermal insulation technology and external wall energy saving insulation materials. Finally, a summary of this paper is made.
摘要：
This research represents an exciting first step towards the use of native grass sod as a tool in the toolbox of best management practices for erosion control and for treating stormwater runoff from highway surfaces. The main "product" from the research is this final project report that documents the background, methodology, and research findings. The intended customers for this product include Caltrans planners, landscape architects, as well as other stakeholders such as highway resource managers. Caltrans decision-makers responsible for roadside vegetation management can benefit from the better knowledge gained from this research on the potential and feasibility of using native grass sod on disturbed land along highways. Information regarding the best native grass species mixes and reinforcement materials can also benefit researchers, sod producers and maintenance engineers for the production, transplantation, maintenance and establishment of native grass sod in California and potentially other states.
作者：
Gong, Jing*;Huang, Ming;Li, Ye;Li, Zhipeng;Li, Ming
作者机构：
[Li, Ye; Gong, Jing; Li, Zhipeng] Wuhan Polytech Univ, Res Inst Architecture, Wuhan 430023, Peoples R China.;[Gong, Jing; Huang, Ming] Wuchang Univ Technol, Coll Urban Construct, Wuhan 430223, Peoples R China.;[Gong, Jing] Wuhan Univ, Res Inst Architecture, Wuhan 430072, Peoples R China.;[Li, Ming] Hubei Yangxin Highway Adm Bur, Huangshi 435200, Peoples R China.
会议名称：
International Conference on Architectural Engineering and New Materials (ICAENM)
会议时间：
JAN 30-31, 2015
会议地点：
Guangzhou, PEOPLES R CHINA
会议主办单位：
[Gong, Jing;Li, Ye;Li, Zhipeng] Wuhan Polytech Univ, Res Inst Architecture, Wuhan 430023, Peoples R China.^[Gong, Jing;Huang, Ming] Wuchang Univ Technol, Coll Urban Construct, Wuhan 430223, Peoples R China.^[Gong, Jing] Wuhan Univ, Res Inst Architecture, Wuhan 430072, Peoples R China.^[Li, Ming] Hubei Yangxin Highway Adm Bur, Huangshi 435200, Peoples R China.
关键词：
Field experiments;erosion control;weed invasion;weed control;soil erosion
摘要：
This experiment was designed to test the hypothesis that multispecies sod has the potential to suppress annual weed invasion. In general, these experiments provided evidence that emergence of canola was low when sown as seed rain or seed bank with multispecies sod and was significantly (p < 0.001) lower the second year after sod was laid. Experiment B results indicated the reinforcement materials did significantly (p < 0.05) further decrease canola emergence in Experiment B-2 (2007). Of the emerged seedlings survival to maturation the vegetative biomass and the seed biomass of these plants was significantly affected by water regime for both the A and B experiments. In contrast, in the reinforcement (B) experiments water regime did not affect survival but the presence of the material increased the proportion of surviving plants. These experiments indicated that multispecies sod could be used as an alternative roadside revegetation technique. It established and survived without supplemental water and reduced weed emergence and survival.
摘要：
This research project will attempt to combine the quick establishment and soil reinforcing properties of sod with the long-term benefits of using native plants. It builds on research by Dollhopf and other scientists in the Land Resources and Environmental Services Department and the Plant Sciences and Pathology Department at MSU. Researchers worked with Bitterroot Turf Farm in Corvallis, Montana to develop, propagate, and test native grass sod for the Montana Department of Transportation. "This foundation research helped us develop methodologies and cost information that we can directly apply in California," said Dollhopf; "We are using our experience selecting, growing, harvesting, and transporting native grass sod in Montana to develop appropriate sods for California.
