Construction and Building Materials最新文献_第10页

Re−utilization of Ca−based and Na−based desulfurization by−product as alternative sulfate activator in supersulfated cement system: Mineral transformation and reaction mechanism

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140838

Shenyu Wang , Xiaowei Gu , Xiaowei Ge , Xu Wang , Ziyang Hu , Jianping Liu , Zhenguo Zhu , Hongyu Wang , Xiaochuan Xu , Moncef L. Nehdi

Expanding the availability scope of sulfate activators in supersulfated cement (SSC) systems will further the development of low–carbon cementitious materials techniques. The use of industrial solid wastes with comparable properties in SSC systems shows significant potential. However, the types of potential sulfate activators and their impacts on SSC performance remain inadequately defined. To address this gap, this study explored the feasibility of substituting gypsum with desulfurization gypsum (DG) and sodium−based desulfurization ash (SDA) as alternative sulfate activators in SSC. The workability, setting time, thermodynamic processes, dissolution characteristics, and mechanical properties of SSC systems prepared with various sulfate activators were characterized comprehensively, and the phase compositions and reaction mechanisms were elucidated using multiple microscopic techniques. The results indicated that fluidity and consistency were primarily dependent on the physical characteristics of the sulfate activators, while setting time was more strongly influenced by chemical dissolution and hydration processes. DG–SSC exhibited thermodynamic, phase composition, and mechanical properties similar to those of G–SSC. The incorporation of SDA increased the system’s pH value and facilitated the dissolution of slags, shifting the product system from ettringite−driven to gel−driven. The formation of gel products optimized matrix densification and enhanced compressive strength. This study not only provides a scientific basis for the application of desulfurization by−products in SSC systems but also offers additional insights into the resource utilization of desulfurization by−products, contributing to the sustainable development of the construction materials industry.

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引用次数: 0

Push-out tests and theoretical models of steel-UHPC composite members considering interfacial bonding strength 考虑界面粘接强度的钢-UHPC 复合材料构件的挤出试验和理论模型

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140856

Youzhu Lin , Mengqi Cao , Xinya Mao , Mingyang Feng , Ming Sun

Recently, ultra-high performance concrete (UHPC) has been incorporated into steel-concrete (SC) composite structures, where the mechanical behaviors at their interfaces play a crucial role in the overall stability. Previous research often overlooks the importance of bonding strength between steel and concrete. To address this gap, this paper introduces a novel test method to measure bonding strength. Twelve push-out specimens were tested to evaluate their mechanical behaviors and failure modes. Three distinct failure modes were identified: concrete cracking failure, connector fracture failure, and a combination of both. The results show that UHPC significantly alters failure modes, shifting from concrete cracking to connector fracture. It also improves shear capacity, increases ductility, and reduces the initial slip modulus. Notably, the bonding strength at the interface contributes to 30 %-40 % of the shear capacity. Finite element models were developed and validated against experimental results. This combination of testing and simulation reveals the influence of UHPC, interfacial bonding strength, and different shear connectors on the structural behavior. Additionally, a parametric study was performed to determine the damage length of concrete near shear connectors, aiding in the development of a theoretical model. Consequently, theoretical models for predicting shear capacity at the steel-concrete interface were developed, specifically considering the interfacial bonding strength. The accuracy of these models has been validated, confirming the applicability in practical engineering design.

最近，超高性能混凝土（UHPC）被应用到钢-混凝土（SC）复合结构中，其界面的力学行为对整体稳定性起着至关重要的作用。以往的研究往往忽视了钢与混凝土之间粘结强度的重要性。为了弥补这一不足，本文介绍了一种测量粘结强度的新型测试方法。对 12 个推出试样进行了测试，以评估其力学行为和破坏模式。确定了三种不同的失效模式：混凝土开裂失效、连接件断裂失效以及两者的结合。结果表明，超高性能混凝土大大改变了破坏模式，从混凝土开裂转变为连接器断裂。它还提高了抗剪能力，增加了延展性，降低了初始滑移模量。值得注意的是，界面处的粘结强度占剪切能力的 30%-40% 。我们开发了有限元模型，并根据实验结果进行了验证。测试与模拟的结合揭示了超高性能混凝土、界面粘结强度和不同剪切连接件对结构行为的影响。此外，还进行了参数研究，以确定剪力连接件附近混凝土的破坏长度，从而有助于理论模型的开发。因此，开发了预测钢-混凝土界面抗剪能力的理论模型，特别是考虑了界面粘接强度。这些模型的准确性已得到验证，证实了其在实际工程设计中的适用性。

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引用次数: 0

Evaluating the impact of nano-silica particle size on pozzolanic reaction kinetics, mechanical strength and durability of portland slag cement

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140784

Jun Xu , Yali Li , Haiting Su , Huichen Xu , Laibo Li , Lingchao Lu

Theoretically, incorporating Nano-silica (NS) into cement-based composites enhances their mechanical properties and durability in marine environment by virtue of nucleation effect, pozzolanic effect and filling effect. However, an investigation on the precise effect of NS particle sizes on PSC performance is lacking. In this paper, the relationship between NS particle size on the reaction kinetics and the mechanical strength and durability of Portland slag cement (PSC) were delved. The reaction kinetics results demonstrated that NS15 displayed the highest pozzolanic activity, but its practical benefits were limited due to the compromised workability of the PSC-NS15. NS30, with its high pozzolanic activity and low rheological effect, showed the best improvement effect on the mechanical properties and durability of PSC. Significantly, compared to the blank sample, PSC-NS30 exhibited a 13.11 % and 8.24 % increase in compressive strength after 3 and 28 days, respectively. Moreover, a notable reduction of 21.64 % in porosity and 12.34 % in chloride diffusion coefficient was observed in PSC-NS30 at 28 days. These findings provide valuable theoretical insights for the judicious selection of NS in marine engineering applications.

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引用次数: 0

Initial commissioning parameters research of full-tailings backfill system in metal mine: From laboratory tests to industrial operation 金属矿全尾矿回填系统的初始调试参数研究：从实验室测试到工业运行

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140811

Chunkang Liu , Hongjiang Wang , Bolin Xiao , Jun Nie , Min Liu

As an extension of the previous investigation which has studied the impact of high-level circulation and floc residence time on underflow concentration and rake torque during initial commissioning of deep cone thickener (DCT), this work carried out the commissioning of the full-tailings backfill system, innovatively translated existing research results in the field of backfill into practical commissioning operation, bridging the gap between theory and practice. The commissioning included three stages: underflow slurry preparation in DCT, backfill slurry (BFS) preparation in mixer, and pipeline transportation. Each stage of commissioning requires support from laboratory tests. During the DCT commissioning stage, static flocculation, dynamic flocculation, and industrial deep cone flocculation tests were conducted to determine key parameters, including the optimal flocculant unit consumption, tailing slurry concentration, tailing feeding flow rate, mud layer height in DCT, floc residence time, and rake torque. In the mixing and pipeline transportation stage, slump, L-pipe, water bleeding, and strength tests were performed to establish the appropriate cement-to-sand ratios, concentration, and flow rate for BFS. The laboratory test methods and parameter results provided a systematic and phased approach to backfill system commissioning, holding significant reference value for the commissioning of backfill system in similar projects. Additionally, relationship models were developed to correlate the flocculant dosage in feed-well with tailing feeding flow rate, the amount of cementitious material added in mixer, and the amount of dilution water introduced during mixing. The application of these models ensures precise materials addition during commissioning, providing a theoretical foundation for the safety and efficiency of the backfill process. Overall, based on the laboratory test results and material addition models, the backfill system has been successfully commissioned, which is of significant importance for understanding the entire process of tailings treatment and backfill from an industrial perspective.

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引用次数: 0

Enhancing the early–age waterproof properties of mortars by incorporating silane and alkyl silicate

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140781

Wei Zhao , Jiang Zhu , Hongtu Li , Jie Zhao , Qiang Dong , Xiaolei Lu , Lina Zhang , Xin Cheng

Water and corrosive ions can easily penetrate into the microstructure of cement–based materials and cause structural damage, given the intrinsic hydrophilic and porous properties of the materials. This paper aimed to enhance the early–age waterproof properties of mortars by incorporating silane and alkyl silicates. The hydration products, pore structure, and microstructure wettability of mortars and cement pastes were analyzed by conducting XRD, TGA, FT–IR, SEM, and MIP measurements. Test results showed that the addition of hydrophobic agents hindered the general hydration of cement and thus deteriorated the pore structure of the mortars. But the early–age waterproof properties of mortars significantly increased, given the enriched distributions of hydrophobic chemicals in the calcium silicate hydrate rich areas where connected pores are prone to exist. The addition of potassium methyl silicate with the emulsion of isobutyltriethoxysilane and sodium dodecyl sulfate (SDS) caused a stable flocculation structure of the SDS, which thus enhanced the dispersion stability of the isobutyltriethoxysilane and increased the hydrophobicity of mortars.

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引用次数: 0

Sustainable clinker-free composites: Effect of mix proportion parameters on hydration and microstructure of steel slag-GBFS-phosphogypsum binder

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140801

Jianwei Sun , Yuehao Guo , Yan Meng , Ling Qin , Ruiquan Jia , Hongyuan Gao , Jie Liu

Steel slag (SS)-GBFS-phosphogypsum (PG) composites is a potential sustainable clinker-free binder. Three important mix proportion parameters were considered: the SS to GBFS ratio (S/G), PG content, and water to binder ratio (W/B). This study systematically explored effects of each parameter on the hydration and microstructure characteristics of the composites. It also evaluated their economic and environmental benefits. Results show that increasing the S/G decreases the exothermic rate. This leads to the formation of a more porous structure at each age. Consequently, the strength and flowability of the composites diminish. At the same time, the setting time and water absorption increase. A decrease in the W/B causes the main exothermic peak to occur earlier. Although the exothermic rate diminishes, this adjustment leads to a denser pore structure at each age. As a result, water absorption and flowability are reduced, the setting time shortens, and strength improves. An increase in PG content results in the main exothermic peak appearing earlier. This is accompanied by a decrease in peak value and an increase in the volume of harmful and more harmful pores at each age. Furthermore, higher PG content reduces flowability and shortens the setting time. Although compressive strength increases at all ages, flexural strength decreases in the later stages. Meanwhile, the water absorption rate rises significantly. After adjusting the three parameters, the hydration products of the composites were still C-(A)-S-H gel and AFt. However, their content decreased. Notably, compared to PC, the composites exhibit marked reductions in CO₂ emissions, production costs, and energy consumption.

钢渣（SS）-GBFS-磷石膏（PG）复合材料是一种潜在的可持续无熟料粘结剂。研究考虑了三个重要的混合比例参数：钢渣与 GBFS 的比例 (S/G)、磷石膏含量以及水与粘结剂的比例 (W/B)。本研究系统地探讨了每个参数对复合材料水化和微观结构特征的影响。研究还评估了其经济和环境效益。结果表明，增加 S/G 会降低放热率。这将导致在每个龄期形成更多的多孔结构。因此，复合材料的强度和流动性都会降低。同时，凝固时间和吸水率也会增加。W/B 值的降低会导致主要放热峰提前出现。虽然放热率降低，但这种调整会导致每个龄期的孔隙结构更加致密。因此，吸水性和流动性降低，凝结时间缩短，强度提高。PG 含量的增加会导致主放热峰提前出现。与此同时，在每个龄期，放热峰值会降低，有害和更有害气孔的体积会增大。此外，PG 含量越高，流动性越差，凝结时间越短。虽然抗压强度在各个龄期都有所提高，但抗折强度在后期却有所下降。同时，吸水率显著上升。调整这三个参数后，复合材料的水化产物仍然是 C-(A)-S-H 凝胶和 AFt，但其含量有所下降。值得注意的是，与 PC 相比，复合材料的二氧化碳排放量、生产成本和能耗都有明显降低。

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引用次数: 0

Experimental investigation on fatigue performance of three typical welded joints of Q420qFNH weathering steel

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140806

Yan Ma , Chuang Cui , Qinghua Zhang , Kun Tang , Zhen-yu Cheng

The novel weathering steel Q420qFNH has significant application potential in modern bridge engineering. This material could meet the urgent demand for high-performance structural materials in contemporary engineering and advance the field of steel material science. In this study, fatigue tests were conducted on three types of Q420qFNH welded joints to obtain their S-N curves and evaluate their fatigue strengths. A comparative analysis was then carried out with existing fatigue codes such as Eurocode 3, IIW, BS 7608, and ANSI/AISC 360 was conducted. A total of 124 pairs of fatigue data were collected from previous studies to analyze the difference in fatigue performance between Q420qFNH welded joints and other traditional structural steels of the same grade by examining the fatigue strength and fatigue resistance index. The results showed that, for all Q420qFNH welded joints, fatigue failure was characterized by multiple crack initiations at the weld toe and their subsequent coalescence and growth along the cross-section near the welding toe. Under the current welding process, the butt-welded (BW) and non-load-carrying cruciform-welded (NCW) joints show that their fatigue strength meet various standards, ensuring safety and reliability. However, load-carrying cruciform-welded (LCW) joints still have room for improving the safety margin. The fatigue strength (P_s=95 %) of BW joints was measured at 88.8 MPa, aligning with the range of 122.7–86.7 MPa seen in other steels of the same grade under as-weld conditions. The NCW joints exhibited a fatigue strength of 103.7 MPa, slightly below the typical range of 112.1–163.9 MPa for ordinary steels under similar conditions. Notably, the LCW joints, featuring near full-penetration welding, demonstrated superior fatigue strength of 76.8 MPa, surpassing most ordinary steels.

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引用次数: 0

Experimental and numerical investigations on thermo-mechanical behaviours of energy pile group with different seepage parameters

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140748

Weibo Yang, Wenxin Xia, Yuhan Qiang, Feng Wang

The operational performance of energy pile (EP) group with seepage is strongly influenced by seepage parameters. In this paper, a model test system of 2 × 2 EP group with seepage is built to study the influences of seepage water level and seepage velocity on thermo-mechanical behaviour of EP group. Also, a numerical model of EP group considering seepage is developed to obtain the variations of thermo-mechanical behaviour of EP group under different seepage parameters. The findings demonstrate that an augmentation in seepage water level can enhance the heat exchange performance of EP group, but it also exacerbate the imbalance of mechanical properties between piles in the short term, in which the seepage only have a significant effect on the temperature of piles and soil below the seepage water level. Increasing seepage velocity and circulating flow rate can strengthen thermal performance of EP group and improve the equilibrium of pile axial force and displacement between the pile groups, but increasing seepage velocity also increases the imbalance of mechanical properties between the front and back rows of pile group. At the same time, compared to the circulating flow rate, the change in seepage velocity has a dominant impact on the thermo-mechanical characteristics of EP group. Moreover, when the seepage angle is within 0–45°, increasing the seepage angle can effectively improve the heat transfer performance of EP group, and the temperature distribution of pile and soil is obviously different for different seepage angles, in which the mechanical properties of EP group have the best equilibrium when the seepage angle is 30° for current simulation conditions.

带渗流的能源桩（EP）群的运行性能受渗流参数的影响很大。本文建立了一个 2 × 2 的带渗流 EP 组模型试验系统，以研究渗流水位和渗流速度对 EP 组热力学行为的影响。此外，还建立了一个考虑到渗流的 EP 组数值模型，以获得 EP 组在不同渗流参数下的热机械性能变化。研究结果表明，渗流水位的增加可提高 EP 组的热交换性能，但也会在短期内加剧桩间力学性能的不平衡，其中渗流仅对渗流水位以下的桩和土的温度有显著影响。提高渗流速度和循环流量可以增强 EP 组的热工性能，改善桩组间桩轴力和位移的平衡，但提高渗流速度也会加剧桩组前后排之间力学性能的不平衡。同时，与循环流量相比，渗流速度的变化对 EP 组热力学特性的影响更大。此外，当渗流角在 0-45° 范围内时，增大渗流角可有效改善 EP 组的传热性能，且不同渗流角下桩土温度分布明显不同，其中在当前模拟条件下，当渗流角为 30° 时，EP 组的力学性能达到最佳平衡。

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引用次数: 0

Investigating the corrosion behaviour of Alloy 34 in a simulated waste sulfuric acid recovery environment

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140813

Minghui Ouyang , Jie Pan , Faming Cai , Chundong Wang , Huan-an Liu , Xueshan Xiao

The corrosion behaviour of super austenitic stainless steel Alloy 34 in a simulated aggressive environment of a waste sulfuric acid recovery system has been investigated. Spontaneous passivation and depassivation of Alloy 34 are observed in 20 % H₂SO₄ and 50 % H₂SO₄ at 80 °C respectively. The depassivation of Alloy 34 can be attributed to the significant dissolution of the protective Cr₂O₃ formed on the surface. The S 2p X-ray photoelectron spectra of the SO₄^2- state indicate that these ions are present on the surface. This suggests that the chemisorption of the counter ions from sulfuric acid may contribute to the observed decrease in corrosion resistance.

引用次数: 0

Interfacial behaviour and shear performance of polarized CFRCM-strengthened corroded RC continuous beams

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials

Pub Date : 2025-03-17 DOI: 10.1016/j.conbuildmat.2025.140786

Panpan Liu , Jing-Pu Tang , Ran Feng , Youhua Fan , Ji-Hua Zhu

This paper investigates the shear performance of corroded reinforced concrete (RC) continuous beams strengthened with polarized carbon fabric reinforced cementitious matrix (CFRCM) plates within an innovative impressed current cathodic protection-structural strengthening (ICCP-SS) repair system. A trilinear cohesive law was developed based on pull-out tests with varying bond lengths to characterize the carbon fabric (CF)-cementitious matrix interface behaviour. Finite element analysis (FEA) incorporating the proposed interface model was conducted on five RC beams to validate critical parameters including failure mechanisms, moment redistribution, load capacity, and shear strength. The interfacial shear stress distribution and CF tensile stress were analyzed. A parametric study comprising 44 numerical models was conducted to evaluate the effects of steel rebar corrosion rate, CF mesh layers, and charge density on shear capacity. The experimental and numerical results were compared with theoretical predictions using ACI 549.4R-20 and the strut-and-tie model (STM). It was concluded that the layered modelling approach for polarized CFRCM composites effectively captured the mechanical response of strengthened specimens. Specifically, while anodic polarization of the first CF layer through ICCP modified the interfacial shear stress distribution, it achieved more uniform interlayer bond behaviour, partially compensating for material degradation. Moreover, despite initial strength reduction due to anodic polarization, the ICCP-SS system significantly enhanced structural durability. Additionally, theoretical predictions using ACI 549.4R-20 showed conservative estimates, while the STM incorporating tensile constitutive behaviour provided more accurate predictions.

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引用次数: 0