期刊：
CONSTRUCTION AND BUILDING MATERIALS,2024年456 ISSN：0950-0618
通讯作者：
Yang, Xiaocong;Lu, S
作者机构：
[Qiu, Zedong; Yang, Xiaocong; Wu, Xiangguo; Lu, Shuang; Tian, Dongyang; Yang, XC; Lv, Maorong; Jiang, Hua] Harbin Inst Technol, Sch Civil Engn, Harbin 150090, Peoples R China.;[Cong, Xinyu] Northeast Forestry Univ, Sch Civil Engn & Transportat, Harbin 150040, Peoples R China.;[Lu, Shuang] China Bldg Mat Acad, State Key Lab Green Bldg Mat, Beijing 100024, Peoples R China.;[Gong, Jing] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.
通讯机构：
[Yang, XC; Lu, S ] H;Harbin Inst Technol, Sch Civil Engn, Harbin 150090, Peoples R China.
关键词：
Polysilicon sludge;Phosphogypsum;Alkali-activated slag;Hydration;Heavy metal leaching
摘要：
Polysilicon sludge (PSS), due to its high organic impurity content, poses significant challenges in solidification using traditional cementitious materials, failing to meet engineering standards. As such, alternative solidification methods are urgently needed to enhance PSS resource utilization. This study explores the use of phosphogypsum (PG) to improve the alkali activation process in the solidification of PSS with slag. Given that calcium sulfate in PG promotes alkali activation, this research investigates the synergistic effects of PG, PSS, and slag as precursors in developing an eco-friendly, resource-efficient solidification approach. Comprehensive characterization techniques, including X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, and solid-state magic-angle spinning nuclear magnetic resonance were employed to assess the influence of PG and PSS dosages on the hydration behavior, mechanical properties, and microstructure of the alkali-activated system. Results demonstrated that the addition of 5 wt% PG significantly improved slag dissolution promoted the formation of hydration products such as hydrated calcium aluminate, reduced sample porosity, and refined the pore size distribution. These effects mitigated the inhibitory impact of PSS on the alkali activation process. However, higher dosages of PG and PSS reduced the system's pH, which in turn hindered early slag solubility and compromised the early strength of the solidified product. In addition, the ternary alkali-activated system developed in this study effectively immobilized heavy metals present in both PSS and PG, thus enabling the synergistic utilization of these waste materials while enhancing environmental compatibility. The findings provide valuable theoretical insights into the use of alkali-activated systems for solidifying waste materials and promote the development of resourceefficient, sustainable waste management strategies. This study paves the way for future research into optimizing the composition of PG, PSS, and slag mixtures to further enhance mechanical performance, long-term stability, and environmental safety.
摘要：
Given the pressing threat of global warming, it is imperative to promote CO2 emission reduction within the cement industry which is widely recognized as a major contributor to the overall carbon footprint. Limestone clay cement (LCC) emerges as a promising alternative to Portland cement. However, to facilitate the implementation of LCC technology, it is urgent to address the low early-age compressive strength issue. Inspired by the successful implementation of nano-engineered cementitious material, we hereby introduce a novel nanomaterial, graphene oxide (GO), into unconventional LCC paste (cement:clay:limestone = 65%:20%:15%, water/binder ratio: 0.45). Experimental results revealed that the 0.09% GO by weight of the LCC binder was the optimal dosage in this work, which improved the compressive strength of the LCC paste at 7, 14, and 28 days by 25.6, 21.6, and 20.3%, respectively. Advanced characterizations were then conducted, suggesting that the admixed GO not only enabled a higher polymerization degree of binder hydrates (which benefited the development of compressive strengths) but also improved the carbonation resistance of LCC paste. These findings not only offer valuable insights for researchers but also provide practical guidance for engineers in the field. Notably, the admixed GO converted the unstable orthorhombic crystal systemic aragonite to the stable trigonal crystal systemic calcite, which offers insights into the technology of carbon sequestration in concrete.
期刊：
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY,2021年21(5):3123-3133 ISSN：1533-4880
作者机构：
[Zhipeng Li; Liang Fan; Xianming Shi] Department of Civil & Environmental Engineering, Washington State University, Pullman, WA 99164-2910, USA;[Jing Zhong] Key Lab of Structure Dynamic Behavior and Control (Harbin Institute of Technology), Ministry of Education, Harbin 150090, Heilongjiang, China;[Zhuo Tang; Jing Gong] School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, China
摘要：
<jats:p>Foamed paste has attracted much attention because of its excellent thermal insulation performance and diverse applications in infrastructure projects. However, there are still some shortcomings hindering the further application of foamed paste, such as the low mechanical strength and
the lack of effective methods to evaluate the properties of foaming bubbles. In this study, surface tension was used as the key parameter to characterize the properties of bubbles. A novel nanomaterial, graphene oxide was employed to enhance the mechanical strength of foamed paste, which was
also effective in decreasing the surface tension of aqueous solution. A central composite design scheme was employed to evaluate the influence of three selected factors, surface tension, Sodium Phosphate/foaming reagents mass ratio, and graphene oxide/binder mass ratio, on the engineering
properties of foamed paste. Additionally, mercury intrusion porosimetry and scanning electron microscope were employed to elucidate the structure of pores, X-ray diffraction and thermogravimetric analysis were employed to further analyze the hydration products at the microscopic scale. This
study reveals that surface tension holds great potential in predicting the engineering properties or performances of foamed paste, and a new mechanism may be developed for explaining the influence of graphene oxide on the pore structure of cementitious materials by evaluating the surface tension
of pore solution.</jats:p>
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.
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, 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.<br/>
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.
