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：
A series of cyclic triaxial tests were conducted on marine soft clay deposits to establish and validate a predictive model for cumulative plastic strain. Additionally, a numerical model of particle flow code in cyclic triaxial tests was developed. The effects of confining pressure, moisture content, and dynamic stress ratio on the dynamic properties of marine soft clay were examined, considering factors such as volume deformation and microscopic failure patterns. The results indicated that both the predictive model and numerical model showed strong consistency with the experimental data. The plastic strain of marine soft clay was influenced by moisture content, stress ratio, and confining pressure in a consistent manner, with moisture content being the primary factor. A predictive model for the cumulative plastic strain of marine soft clay was successfully established, allowing for the evaluation of dynamic properties from the perspective of cumulative plastic strain. During the loading process in the numerical model, microcracks within the soil structure gradually compacted, and the main displacement of the specimen extended from the vertical center axis to the sides, ultimately resulting in shear damage.
摘要：
Nowadays, geopolymer coatings have been studied a lot due to their green and sustainable properties, and they have a great potential to partially replace traditional coatings in terms of corrosion resistance and economy. In this study, metakaolin-based geopolymer coating was used as the control group, and anticorrosive coatings were prepared by adding different dosages (2-8 wt%) of ZnO fillers to study the effect of ZnO on physical properties and anticorrosion properties of metakaolin-based geopolymer anticorrosive coatings. The results showed that when the mass fraction of the zinc oxide was 8%, it had the optimum effect on physical performance. The water absorption was 12.4%, and the toughness was 3 mm. In addition, the anticorrosive properties of the coating were studied by sodium chloride (NaCl) solution immersion test, wet-dry cyclic test, salt spray test, and electrochemical test. In sodium chloride (NaCl) solution immersion, wet-dry cycle, and salt spray test, a reduction of 43.8%, 50.6%, and 74.2% in corrosion area ratio, respectively, were achieved with a coating of 8% ZnO filled as compared with pure geopolymer coatings. The results indicated that the addition of ZnO enhanced the anticorrosion performance of the coating. The macroscopic test results were verified by SEM. This study lays a foundation for the subsequent research and performance improvement of metakaolin-based geopolymer anticorrosive coatings.
摘要：
Phase change energy storage technology using phase change materials (PCMs) is a viable solution to effectively address the heat dissipation problems of electronic devices. Herein, we proposed to prepare a modified PCM using CH3COONa center dot 3H(2)O (SAT) as main PCM, 9 wt% DL-Alanine (DL) as temperature modifier, and 2 wt% Na2HPO4 center dot 12H(2)O as nucleating agent. Calculations using density functional theory method confirmed that the adjustment of DL on phase change temperature of SAT was originated from the hydrogen bond between them. Then, the modified PCM was loaded into 14 wt% expanded graphite (EG) to obtain a composite PCM with a suitable phase change temperature of 52.9 degrees C, phase change enthalpy of 227.4 J/g as well as supercooling degree of 6.6 degrees C, and the thermal conductivity of the composite PCM was as high as 11.52 W.m(-1).K-1. SEM and pore structure analyses showed that the modified PCM was successfully loaded into the pore structure of EG, and their combination was verified by XRD and FT-IR as a physical interaction. After 200 heating-cooling cycles, the phase change temperature and enthalpy of the composite PCM was basically unchanged along with consistent crystal structure and chemical composition, showing an excellent thermal reliability. A comparative analysis applied in a testing system showed that with loading of the composite PCM temperature control module, the critical time of the electronic chip was extended by 4670 s and the thermal equilibrium temperature was decreased by 20.4 degrees C, presenting a good thermal management performance. Therefore, the prepared composite PCM had great potential for application in thermal management of electronic devices.
摘要：
This paper examines the feasibility of the natural soil and sewage sludge ash (SSA) mixtures, which satisfy the criteria to be used as landfill liners. The effect of SSA content on hydraulic conductivity and strength characteristics of natural soil and SSA mixtures has been investigated through a series of laboratory tests. The results demonstrate that mixtures exhibit an increase in both hydrodynamic diffusion coefficient and strength with the increasing SSA content. With the content of SSA from 0% to 5%, the values of the hydrodynamic diffusion coefficient (D) ranged from 3.5 × 10(-10) to 15 × 10(-10) cm(2)/s. The increase in the hydrodynamic diffusion coefficient is minor for low SSA content and significant for SSA content exceeding 5%. The inclusion of 5% SSA content results in a hydrodynamic diffusion coefficient that is approximately three times higher than that observed in natural soil. The results were obtained from soil triaxial tests, revealing that the mixtures containing SSA exhibited a significant increase in both the initial tangent modulus and the ultimate principal stress difference compared to those of natural soil. The SSA content with the highest value exhibits maximum initial tangent modulus and ultimate principal stress. The comprehensive analysis of the strength and hydraulic diffusion conductivity of the mixtures demonstrates that the incorporation of 3% SSA results in a significant enhancement in strength, while marginally increasing hydrodynamic diffusion coefficients. Therefore, it can be inferred that the utilization of mixtures containing 3% SSA content as a liner material is suitable.
摘要：
Landfills necessitate a liner barrier system to prevent the leakage of contaminants into the surrounding soil. However, the currently employed compacted clay liner (CCL) is insufficient to prevent the leakage of heavy metal ions. This study proposes a novel landfill liner system utilizing sludge-based activated carbon (SAC)-modified clay. The adsorption characteristics of SAC-modified clay liner (SAC-CCL) for Cd(II) or Cu(II) were evaluated through batch tests. The permeability coefficient and unconfined compressive strength of SAC-CCL were assessed through permeation and unconfined compression tests. The permeability coefficient of the SAC-modified clay ranged from 2.57 x 10(-9) to 1.10 x 10(-8) cm/s. The unconfined compressive strength of the SAC-CCL varied between 288 and 531 kPa. The migration of Cd(II) or Cu(II) within an 80 cm thick, full-scale SAC-CCL was simulated using soil column tests. The diffusion coefficient (D) was calculated by inversion using the one-dimensional solute migration equation. The diffusion coefficients (D) for Cd(II) and Cu(II) ranged from 1.9 x 10(-10) to 13.5 x 10(-10) m(2)/s. The retardant performance of SAC-CCL for Cd(II) and Cu(II) followed the order: 3% SAC-CCL > 1% SAC-CCL > CCL > 5% SAC-CCL, from strongest to weakest. Consequently, SAC-modified clay demonstrates significant potential as a landfill lining material. However, the migration behavior of heavy metal ions in SAC-CCLs under cyclic dry-wet conditions requires further investigation.
摘要：
本文利用醋酸乙烯酯-乙烯共聚乳液(EVA)、丙烯酸酯乳液(PAE)分别对装配式水泥基套筒灌浆料进行改性，制备了2种聚合物乳液改性套筒灌浆料。研究了聚合物乳液对套筒灌浆料流动度、抗压强度、吸水率、膨胀率、耐久性、拉伸性能和微观结构的影响，并进行了成本核算。结果表明：掺入聚合物乳液能显著改善灌浆料的流动度、抗压强度、吸水率、抗硫酸盐侵蚀和抗冻融侵蚀性能，而且PAE改性的套筒灌浆料的综合性能优于EVA改性；PAE改性能增强灌浆料整体内聚力和密实度，使得灌浆料的膨胀率基本无负面影响且无泌水现象，同时可以增强灌浆料接头的拉伸性能、抗拉强度以及黏结强度。当PAE掺量在0.3%~1.0%(质量分数)时，PAE改性灌浆料性能均满足相应国家标准要求，且制备成本较低。 您的浏览器不支持 audio 元素。AI语音播报 In this study, two kinds of polymer emulsion-modified sleeve grouting materials were prepared with vinyl acetate-ethylene copolymerization emulsion (EVA) and acrylate emulsion (PAE), respectively. The effects of polymer emulsion on the fluidity, compressive strength, water absorption, expansion rate, durability, tensile property and microstructure of the sleeve grouting material were investigated and its cost accounting was executed. The results show that polymer emulsion can significantly improve the fluidity, compressive strength, water absorption, sulfate resistance and freeze thaw resistance of grouting materials, and the comprehensive properties of PAE modified sleeve grouting materials are better than EVA modified ones. PAE modification enhances the overall cohesion and density of grouting material, ensuring that the expansion rate of the grouting material has little negative impact and no bleeding phenomenon. At the same time, it can enhance the tensile performance, tensile strength, and bonding strength of grouting material joint. When the PAE content is between 0.3% and 1.0% (mass fraction), the performance of PAE modified grouting material meets the corresponding national standard requirements, and the preparation cost is relatively low.
摘要：
The influence of polymer emulsion, pigment filler, and dispersant on the corrosion resistance of polymer cement-based composite anti-corrosion coatings were investigated in this study. Adhesion loss rate tests and electrochemical tests were conducted on samples. The research results show that optimal corrosion resistance can be achieved with a 45 wt% dosage of emulsion, a 6 wt% dosage of pigment filler, and a 0.30 wt% dosage of dispersant. The bonding properties of bare steel bars, epoxy-coated steel bars, and polymer cement-based composite anti-corrosion coated steel bars with grout were compared. The results show that the polymer cement-based composite anti-corrosion coating can enhance the bonding properties of the samples. Furthermore, the microscopic analysis was conducted on the samples. The results demonstrate that the appropriate addition of emulsion can fill internal pores of the coating, tightly bonding hydration products with unhydrated cement particles. Moreover, incorporating a suitable dosage of functional additives enhances the stability of the coating system and leads to a denser microstructure.
摘要：
Enzyme-induced carbonate precipitation (EICP) is a promising technique for soil reinforcement. To select a suitable calcium source and a suitable solution amount for aeolian sand stabilization using EICP, specimens treated with different solution amounts (1.5, 2, 2.5, 3, and 3.5L/m(2)). Surface strength, crust thickness, calcium carbonate content (CCC) and water vapor adsorption tests were performed to evaluate the effect of two calcium sources (calcium acetate and calcium chloride) on aeolian sand solidification. The plant suitability of solidified sand was investigated by the sea buckthorn growth test. The suitable calcium source was then used for the laboratory wind tunnel test and the field test to examine the erosion resistance of solidified sand. The results demonstrated that Ca(CH(3)COO)(2)-treated specimens exhibited higher strength than CaCl(2)-treated specimens at the same EICP solution amount, and the water vapor equilibrium adsorption mass of Ca(CH(3)COO)(2)-treated specimens was less, indicating that Ca(CH(3)COO)(2)-solidified sand was more effective and had better long-term stability. In addition, plants grown in Ca(CH(3)COO)(2)-treated sand had greater seedling emergence percentage and higher average height, which indicated that calcium acetate is a more suitable calcium source for EICP treatment. Furthermore, the surface strength and crust thickness of solidified sand increased with increasing the solution amount. For sand treated with 3L/m(2) of solution, the excessive strength and thickness of the crust made plants growth difficult, and the performance of sand treated with more than 2L/m(2) of solution significantly improved. Thus, the solution amount of 2-3L/m(2) is suggested for engineering applications. The sand solidified using EICP in the field could effectively mitigate wind erosion and facilitate the growth of native plants. Therefore, EICP can be combined with vegetative method to achieve long-term wind erosion control in the future.
摘要：
Lamb's Problem, a cornerstone in theoretical seismology, investigates the displacement of an elastic half-space due to surficial or buried point sources. Although the exact closedform solution for surface displacements from surficial sources is well established, the solutions for buried sources in the 3D case have remained limited, either confined to integral forms or applicable only for certain Poisson's ratios. This study addresses this gap by generalizing the existing closed-form solutions to accommodate Poisson's ratio for buried sources. Our solutions are expressed in terms of elementary algebraic expressions, elliptic integrals, and Gauss hypergeometric functions. The derived solution is validated by numerical tests. With the newly derived solution, we also explore the properties of the leaking mode, which stems from the complex conjugate roots of the Rayleigh equation.
