Case Studies in Construction Materials最新文献_第4页

Research on the practical application of self-healing calcium alginate capsules in asphalt pavements in Fujian province 自愈海藻酸钙胶囊在福建省沥青路面中的实际应用研究

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-24 DOI: 10.1016/j.cscm.2025.e05730

Hang Chen , Peixin Zhong , Jiazhu Wang , Zirong Ma , Shaopeng Wu , Quantao Liu , Yilun Shen , Xiaobin Zou , Aimin Sha , Pei Wan , Niecheng Lin , Zhiming Lin , Xinling Feng , Qiuyuan Luo , Pengjuan Zhang , Jixin Zhang , Jinqing Wang , Lei Zhang , Huan Wang , Xing Gong

Asphalt pavement maintenance faces challenges from crack propagation and material aging, prompting the exploration of innovative self-healing technologies. Traditional maintenance methods such as grouting and patching, are reactive and short-term. This study investigates the practical application of self-healing calcium alginate capsules in asphalt pavements to address performance degradation caused by traffic loads and environmental factors. The research team have developed an integrated production device for large-scale manufacturing of calcium alginate capsules. These capsules containing low-viscosity asphalt rejuvenator are incorporated into AC-13 asphalt mixtures and applied to test road section in Yongtai S213 Line, Fujian Province. Field tests demonstrate that the capsule-modified pavement met construction specifications, with compaction (97.8 %), texture depth (0.80 mm), and permeability (242 ml/min) within acceptable ranges. Although the capsules slightly reduced mixture density, marshal stability and dynamic stability compared to conventional asphalt, all parameters complied with Chinese standards. The study validates the feasibility of calcium alginate capsules for self-healing asphalt pavements, highlighting their potential to extend service life through crack repair and aged asphalt regeneration. Challenges remain in optimizing production scalability and long-term durability for broader engineering applications.

沥青路面养护面临着裂缝扩展和材料老化的挑战，促使人们探索创新的自愈技术。传统的维修方法，如灌浆和修补，是反应性和短期的。本研究探讨自愈海藻酸钙胶囊在沥青路面上的实际应用，以解决交通负荷和环境因素造成的路面性能下降问题。研究小组开发了大规模生产海藻酸钙胶囊的集成生产装置。这些含有低粘度沥青再生剂的胶囊被掺入AC-13沥青混合料中，用于福建省永泰S213线试验路段。现场试验表明，胶囊改性路面的压实度（97.8% %）、纹理深度（0.80 mm）和渗透性（242 ml/min）均在可接受范围内，满足施工要求。虽然与常规沥青相比，胶囊的混合料密度、marshal稳定性和动力稳定性略有降低，但所有参数均符合中国标准。该研究验证了海藻酸钙胶囊用于自愈沥青路面的可行性，强调了其通过裂缝修复和老化沥青再生来延长使用寿命的潜力。为更广泛的工程应用优化生产可扩展性和长期耐用性仍然存在挑战。

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引用次数: 0

Enhancing the toughness and low-temperature performance of epoxy asphalt via PTMG-MDI modified epoxy resin 通过pmmg - mdi改性环氧树脂提高环氧沥青的韧性和低温性能

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-09 DOI: 10.1016/j.cscm.2026.e05785

Yitong Hou , Qiqi Zhan , Xinqiang Zhang , Bailin Shan , Liming Yang , Pan Liu , Yanan Cui

Epoxy asphalt is widely applied in steel bridge deck paving due to its high strength and thermal stability. However, the thermosetting epoxy resin becomes highly brittle after curing, resulting in insufficient toughness and poor low-temperature crack resistance. To address this issue, a novel high-toughness epoxy asphalt (HTEA) was developed by grafting polytetramethylene ether glycol-diphenylmethane diisocyanate (PTMG-MDI), serving as polyurethane flexible segments, onto epoxy resin and incorporating it into asphalt. The cured high-toughness epoxy resin (HTER) exhibited good thermal stability and mechanical properties, with a tensile strength of 4.05 MPa and an elongation at break of 143 %. HTEA showed slightly reduced tensile strength but significantly increased elongation at break. Rheological tests indicated that the retention time of HTEA reached up to 37 min. The storage modulus decreased in the low-temperature region, while the high-temperature creep compliance changes only slightly, indicating improved creep recovery performance. The fracture morphologies of HTER and HTEA exhibits ductile characteristics. The PTMG-MDI increases the density of cross-linking points in the three-dimensional network, thereby improving the low-temperature crack resistance of epoxy asphalt. When the HTER content is 40 % the glass transition temperature of HTEA is as low as −28.7℃, and the testing temperature is −24℃, the maximum creep modulus reaches 492 MPa, with a minimum creep rate of 0.242, indicating excellent low-temperature performance.

环氧沥青因其强度高、热稳定性好而广泛应用于钢桥面铺装。但热固性环氧树脂固化后变脆，韧性不足，耐低温开裂性差。为了解决这一问题，将聚四亚甲基醚乙二醇二苯基甲烷二异氰酸酯（PTMG-MDI）作为聚氨酯柔性段接枝到环氧树脂上，并将其掺入沥青中，开发出一种新型高韧性环氧沥青（HTEA）。固化后的高韧性环氧树脂（HTER）具有良好的热稳定性和力学性能，抗拉强度为4.05 MPa，断裂伸长率为143 %。HTEA的抗拉强度略有降低，但断裂伸长率显著提高。流变试验表明，HTEA的滞留时间可达37 min。低温区存储模量降低，而高温蠕变柔度变化不大，表明蠕变恢复性能有所提高。HTER和HTEA的断裂形貌表现出延性特征。pmmg - mdi增加了三维网络中交联点的密度，从而提高了环氧沥青的低温抗裂性。当HTER含量为40 %时，HTEA的玻璃化转变温度低至−28.7℃，试验温度为−24℃，最大蠕变模量达到492 MPa，最小蠕变速率为0.242，低温性能优良。

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引用次数: 0

Impact of lime kiln dust on the mechanical properties and freeze-thaw durability of nanoclay-stabilized kaolin soil 石灰窑粉尘对纳米粘土稳定高岭土力学性能和冻融耐久性的影响

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-07 DOI: 10.1016/j.cscm.2026.e05774

Maryam Majd Rahimabadi , Mahyar Arabani

Stabilization of clayey soils using traditional stabilizers such as lime and cement raises significant environmental concerns. Recent studies have shown that despite the strength limitations of nanoclay (NC) and the slow rate of pozzolanic reactions associated with lime kiln dust (LKD) in soil stabilization, these materials exhibit promising performance as environmentally friendly stabilizers. This study investigates the combined effects of NC and LKD with the aim of overcoming these limitations and improving the mechanical behavior and durability of kaolin soil. Laboratory testing included mechanical and durability tests supported by microstructural analyses. The results indicate that the addition of LKD to NC-treated soil resulted in an approximately tenfold increase in both unconfined compressive strength and indirect tensile strength. These improvements are attributed to pore filling by NC and the occurrence of pozzolanic reactions induced by LKD, leading to the formation of C–S–H and C–A–H gels. Mechanical strength increased with curing time due to the gradual completion of pozzolanic and hydration reactions. Furthermore, the stabilizers improved durability and CBR values, reduced the required pavement thickness by 65.7 %, and resulted in significant cost savings in highway construction. In addition, compared with cement and lime, the use of these additives reduced CO₂ emissions by approximately threefold and decreased energy consumption by more than tenfold.

使用石灰和水泥等传统稳定剂稳定粘土引起了严重的环境问题。最近的研究表明，尽管纳米粘土（NC）的强度有限，并且与石灰窑粉尘（LKD）相关的火山灰反应速度缓慢，但这些材料作为环境友好型稳定剂表现出很好的性能。为了克服这些限制，提高高岭土的力学性能和耐久性，本研究探讨了NC和LKD的联合作用。实验室测试包括由微观结构分析支持的机械和耐久性测试。结果表明，添加LKD后，nc处理土的无侧限抗压强度和间接抗拉强度均提高了约10倍。这些改善是由于NC填充孔隙和LKD诱导的火山灰反应的发生，导致C-S-H和C-A-H凝胶的形成。由于火山灰反应和水化反应的逐渐完成，机械强度随固化时间的延长而增加。此外，稳定剂提高了耐久性和CBR值，将所需的路面厚度减少了65.7% %，从而显著节省了公路建设成本。此外，与水泥和石灰相比，这些添加剂的使用减少了大约三倍的二氧化碳排放量，减少了十倍以上的能源消耗。

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引用次数: 0

Revealing fly ash induced cement hydration retardation: The application of embedded integrated sensing element and coda wave analysis 揭示粉煤灰诱导水泥水化迟滞：嵌入式集成传感元件与尾波分析的应用

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-07 DOI: 10.1016/j.cscm.2025.e05747

Yuanxing Wang , Weiwei Xu , Ming Sun , Pingfeng Li , Shijie Wang , Weijian Ding , Lei Qin , Yu Liang , Yu Wang

Fly ash (FA) is a common supplementary cementitious material and it delays early cement hydration. This study applies a novel integrated sensing element (ISE) to monitor cement hydration and to characterize the influence of FA. The results show that signals evolve with hydration. Amplitude shows an early decrease followed by recovery. Energy exhibits a rapid drop and then a gradual increase, and the time to reach the minimum energy is delayed by 9.36 %, 14.61 %, 19.10 %, 22.85 %, and 33.08 % for 5 %, 10 %, 15 %, and 20 % FA compared with 0 % FA. The dominant frequency band remains within 140–170 kHz, while the peak magnitude in the frequency domain evolves more slowly as FA content increases. The coda wave is sensitive to microstructural development and shows slower evolution with higher FA, which indicates inhibition of early hydration. Coda wave analysis at multiple times confirms this slowdown. Setting time tests show reductions of 4 %, 9 %, 14 %, 22 %, and 28 % in the initial setting time, and wave velocity measurements show decreases in shear (1018–862 m/s) and longitudinal (2175–2012 m/s) velocities with increasing FA. These consistent results demonstrate the feasibility of ISE for in situ detection of hydration retardation in cementitious materials that contain FA.

粉煤灰是一种常见的补充胶凝材料，它会延缓水泥的早期水化。本研究采用一种新型集成传感元件（ISE）来监测水泥水化并表征FA的影响。结果表明，信号随水合作用的变化而变化。振幅显示早期下降，随后恢复。能源展览迅速下降,然后逐渐增加,和时间达到最小能量是推迟了9.36 % 14.61 % 19.10 %, % 22.85和33.08 % 5 %,10 % 20 15 %,% FA与0 %。主导频带保持在140 ~ 170 kHz范围内，而随着FA含量的增加，频域峰值幅度的变化更慢。尾波对微结构发育较为敏感，且随着FA的升高，尾波演化较慢，说明早期水化受到抑制。多次尾波分析证实了这种减速。凝结时间试验表明，初始凝结时间降低了4 %、9 %、14 %、22 %和28 %，波速测量表明，随着FA的增加，剪切速度（1018-862 m/s）和纵向速度（2175-2012 m/s）降低。这些一致的结果证明了ISE在含有FA的胶凝材料中原位检测水化延迟的可行性。

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引用次数: 0

Study on mechanical properties and microscopic mechanism of expansive soil improved by eggshell ash-silica fume composite 蛋壳灰-硅灰复合材料改良膨胀土力学性能及细观机理研究

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-09 DOI: 10.1016/j.cscm.2025.e05666

Qingrui LU , Rong Hu , Zihan Wu , Jinhe Gao

To reduce the high carbon emissions of traditional modifiers (cement/lime) and address gaps in ESA–SF studies—unclear dosage-age-performance relations and insufficient micro-mechanism and durability analysis. Weak expansive soil from Huainan City, China, was stabilized using ESA and SF—both obtained from solid wastes. Macroscopic tests (free swelling ratio, unconfined compressive strength, direct shear strength) and microscopic analyses (XRD, SEM, dry–wet cycling) were conducted to evaluate the effects of ESA content (0 %, 3 %, 6 %, 9 %), SF content (0 %, 4 %, 8 %, 12 %), and curing age (1 d, 7 d, 14 d, 28 d). The results demonstrated that the composite of 9 % ESA + 8 % SF effectively reduced the free swelling ratio to below 20 % after 28 days, converting the soil to non-expansive. An unconfined compressive strength of 1.90 MPa was achieved at 28 days, with the stress–strain curve showing an excellent fit. Under 300 kPa vertical pressure, the shear strength increased to 279.49 kPa, accompanied by a 292.15 % rise in cohesion and a 43.6 % increase in the internal friction angle compared to plain soil. Microstructural analysis indicated that Ca2⁺ from ESA compressed the double layer, while SF reacted with Ca(OH)₂ to form C-S-H gels. After seven dry-wet cycles, the stabilized soil retained 40 % of its strength, whereas plain soil collapsed after only three cycles. Overall, the optimal 9 % ESA + 8 % SF formulation effectively mitigates expansion-contraction hazards, enhances long-term soil stability, and exemplifies waste-to-resource utilization consistent with carbon neutrality objectives, offering an economically viable, environmentally sustainable, and technically robust solution for expansive soil engineering applications.

减少传统改性剂（水泥/石灰）的高碳排放，解决ESA-SF研究中的空白——剂量-龄期-性能关系不明确以及微观机制和耐久性分析不足。对淮南市软弱膨胀土进行了固体废弃物中ESA和sfs稳定化处理。通过宏观试验（自由膨胀比、无侧限抗压强度、直剪强度）和微观分析（XRD、SEM、干湿循环），评价了ESA含量（0 %、3 %、6 %、9 %）、SF含量（0 %、4 %、8 %、12 %）和养护龄期（1 d、7 d、14 d、28 d）的影响。结果表明：9 % ESA + 8 % SF复合处理28 d后，有效地将自由膨胀率降低至20 %以下，使土体转为非膨胀状态。28 d无侧限抗压强度为1.90 MPa，应力-应变曲线拟合良好。竖向压力为300 kPa时，抗剪强度达到279.49 kPa，黏聚力比平原土提高292.15 %，内摩擦角比平原土提高43.6 %。微观结构分析表明，来自ESA的Ca2+压缩了双层膜，而SF与Ca(OH)2反应形成C-S-H凝胶。经过7次干湿循环，稳定土的强度保持了40% %，而平原土只经过3次循环就发生了崩塌。总体而言，最佳的9 % ESA + 8 % SF配方有效地减轻了膨胀-收缩危害，增强了土壤的长期稳定性，并体现了与碳中和目标一致的废物转化为资源的利用，为膨胀土工程应用提供了经济上可行、环境上可持续、技术上稳健的解决方案。

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引用次数: 0

Investigation on the high-temperature rutting failure of asphalt pavement structures under the combined effect of measured temperature and applied load 实测温度与外加荷载共同作用下沥青路面结构高温车辙破坏研究

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-17 DOI: 10.1016/j.cscm.2025.e05711

Tengfei Nian , Baosen Wu , Jiaqi Song , Mingjuan Zhang

The semi-rigid base pavement in the Jiayuguan area experiences significant challenges, particularly rutting deformation resulting from the combined effects of high-temperature weather and vehicle loads. By collecting meteorological data from the Jiayuguan area and inputting 24-hour temperature and solar radiation values during summer high-temperature periods, a solid heat transfer physical field and a surface radiation physical field were established to analyze the temperature distribution within the pavement structure. Two typical pavement materials, AC-16 and SMA-16, were selected as asphalt surface materials, with numerical simulations performed using the finite element software COMSOL Multiphysics to study asphalt pavement under combined environmental and vehicle loading conditions. Considering the temperature-dependent properties of asphalt mixtures (e.g., elastic modulus, creep coefficient), solid mechanical physical fields and vehicle load models were developed to estimate the mechanical response and rutting deformation of asphalt pavement under continuous temperature and load coupling conditions. The results indicate that the daily road surface temperature variation reaches 33.89°C, significantly impacting the material properties of asphalt mixtures. Under the combined effects of temperature and load, the mechanical response trends for pavements with AC-16 and SMA-16 surface materials are similar. Maximum vertical deformation, shear creep, and compressive creep all occur within the top 0–4 cm pavement depth, alternating between positive and negative across the transverse direction of the pavement. Compared to AC-16, SMA-16 exhibits reductions of 63.4 %, 22.4 %, 42.89 %, 45.29 %, 46.85 % and 27.19 % in positive and negative vertical deformations, making SMA-16 more suitable for enhancing the rutting resistance of asphalt pavement.

嘉峪关地区的半刚性基层路面面临着严峻的挑战，尤其是高温天气和车辆荷载共同作用下的车辙变形。通过收集嘉峪关地区的气象资料，输入夏季高温时期24小时的温度和太阳辐射值，建立固体传热物理场和表面辐射物理场，分析路面结构内部温度分布。选取AC-16和SMA-16两种典型路面材料作为沥青路面材料，利用COMSOL Multiphysics有限元软件对环境和车辆荷载复合条件下的沥青路面进行数值模拟。考虑沥青混合料的温度相关特性（如弹性模量、蠕变系数），建立了实体力学物理场和车辆荷载模型，以估计沥青路面在连续温度-荷载耦合条件下的力学响应和车辙变形。结果表明：路面温度日变化达到33.89℃，显著影响沥青混合料的材料性能；在温度和荷载共同作用下，AC-16和SMA-16路面的力学响应趋势相似。竖向变形最大值、剪切蠕变最大值和压缩蠕变最大值均出现在0 ~ 4 cm路面深度顶部，在路面横向上呈正负交替变化。与AC-16相比，SMA-16的正、负竖向变形量分别降低了63.4 %、22.4 %、42.89 %、45.29 %、46.85 %和27.19 %，更适合用于提高沥青路面抗车辙性能。

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引用次数: 0

Effect of Hybrid Surface Treatment of Tire Rubber Aggregates on the microstructure and mechanical properties of Standardized Mortars 轮胎橡胶集料复合表面处理对标准砂浆微观结构和力学性能的影响

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-23 DOI: 10.1016/j.cscm.2025.e05721

Achouak Yousfi , Habib Abdelhak Mesbah , Mohamed Saadi

The incorporation of tire rubber aggregates in cement-based mortars reduces the consumption of natural sand but typically leads to substantial strength losses because of the weak and porous interfacial transition zone (ITZ) formed around untreated rubber. This study develops a hybrid mineral-epoxy surface treatment designed to overcome this limitation by forming a continuous composite shell composed of sand, cement, silica fume and epoxy resin. Microstructural analyses show that the treatment yields a uniformly coated rubber surface, a denser particle morphology and a markedly refined ITZ: the interfacial layer around untreated rubber is wide and highly porous (≈14–15 µm), whereas the hybrid coating reduces it to a compact band of about 1–2 µm. These refinements translate into consistent mechanical gains across all curing ages, with flexural strength increasing by 11–27 % and compressive strength by 23–76 %, depending on substitution level and age. In parallel with these mechanical and microstructural improvements, the method offers a favourable cost-performance balance, particularly thanks to the possibility of reducing resin consumption through optimisation of the adhesive film. The hybrid coating concept significantly strengthens the feasibility of producing high-performance and economically viable rubberized mortars and, ultimately, rubberized concretes.

在水泥基砂浆中掺入轮胎橡胶骨料可以减少天然砂的消耗，但由于在未经处理的橡胶周围形成了弱而多孔的界面过渡区（ITZ），因此通常会导致大量强度损失。本研究开发了一种混合矿物-环氧树脂表面处理方法，旨在通过形成由砂、水泥、硅灰和环氧树脂组成的连续复合外壳来克服这一限制。微观结构分析表明，处理后的橡胶表面涂覆均匀，颗粒形态致密，ITZ明显细化：未处理橡胶周围的界面层宽且多孔（≈14-15 µm），而杂化涂层将其缩小到约1-2 µm的致密带。这些改进转化为所有龄期的一致力学增益，根据替代水平和龄期的不同，抗弯强度提高11-27 %，抗压强度提高23-76 %。与这些机械和微观结构的改进并行，该方法提供了有利的成本-性能平衡，特别是由于通过优化胶膜减少树脂消耗的可能性。混合涂层概念大大加强了生产高性能和经济可行的橡胶砂浆的可行性，并最终生产橡胶混凝土。

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引用次数: 0

Effects of freeze-thaw conditions and salt content on porosity and pore size distribution of chloride silty clay 冻融条件和含盐量对氯质粉质粘土孔隙率和孔径分布的影响

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-29 DOI: 10.1016/j.cscm.2025.e05743

Yaqin Zhang , Ping Yang , Linliang Han , Rongkai Pan

Artificial ground freezing (AGF) technology is frequently utilized to ensure tunnel stability during the construction of undersea tunnels. However, freeze-thaw cycles cause substantial alterations in the soil’s porosity and pore size distribution, which can result in deformation and even collapse of the soil. Therefore, it is imperative to thoroughly explore the impact of freeze-thaw and salt content on the porosity and pore size distribution of soil. For this reason, two tests, namely X-ray computed tomography technology (CT) test and Nuclear magnetic resonance spectroscopy technology (NMR) test were performed on the silty clay at different freeze-thaw conditions (freeze-thaw FT cycle: 0, 1; freezing temperature: −10 ℃, −20 ℃, −30 ℃) and salt contents (0 %, 1 %, 2 %, 3 %, 4 %) in this study. The test results revealed that after freeze-thaw, the total porosity increased, with higher freezing temperatures resulting in greater total porosity. As the salt content increased, the total porosity initially increased and then decreased. The porosity in both the XZ and YZ planes followed a normal distribution, while multiple peaks appeared in the XY plane with the smallest coefficient of variation. The porosity uniformity in the vertical direction of the specimen was good, and the spatial anisotropy was significant. Freeze-thaw led to a reduction in the number of micropores, while simultaneously causing an increase in pore size. Moreover, the conversion rate of micropores to macropores decreased as the freezing temperature lowered. The total porosity measured by CT test was much smaller than that of NMR test. The pore size distribution curves derived from NMR and CT tests were found to be complementary. The method for constructing full-size pore size distribution curves containing different scales was proposed. The results provide important perspectives on the microstructure characteristics of marine soft clay under the application of AGF technology.

在海底隧道施工中，为了保证隧道的稳定性，经常采用人工冻结技术。然而，冻融循环会使土壤的孔隙度和孔径分布发生重大变化，从而导致土壤变形甚至坍塌。因此，深入研究冻融和含盐量对土壤孔隙度和孔径分布的影响势在必行。为此，本研究对粉质粘土在不同冻融条件下（冻融FT循环：0,1，冻结温度：−10℃，−20℃，−30℃）和含盐量（0 %,1 %,2 %,3 %,4 %）进行了x射线计算机断层扫描技术（CT）试验和核磁共振波谱技术（NMR）试验。试验结果表明，冻融后总孔隙度增大，冻结温度越高，总孔隙度越大。随着含盐量的增加，总孔隙度先增大后减小。XZ和YZ平面孔隙度均服从正态分布，而XY平面孔隙度呈多峰分布，变异系数最小。试样纵向孔隙度均匀性好，空间各向异性显著。冻融导致微孔数量减少，同时导致孔隙尺寸增大。随着冻结温度的降低，微孔向大孔的转化率降低。CT试验测得的总孔隙率远小于核磁共振试验。由核磁共振和CT测试得到的孔隙大小分布曲线是互补的。提出了构建含不同尺度的全尺寸孔径分布曲线的方法。研究结果为研究AGF技术作用下海洋软粘土的微观结构特征提供了重要视角。

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引用次数: 0

Carbonation hardening of EAF slag-based binders using CO2 under low and supercritical pressure conditions 低压和超临界条件下CO2对电炉渣基粘结剂的碳化硬化研究

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-06 DOI: 10.1016/j.cscm.2026.e05763

João Castro-Gomes , Jaime Orellana-Barrasa , Geovane Bezerra Junior , Erick Grünhäuser Soares , Leszek Szojda , José Carlos Gonçalves , José Ygnacio Pastor , Antonia Pacios-Álvarez

This study investigates the influence of CO₂ pressure regimes on the carbonation hardening of electric arc furnace (EAF) slag binders. Ten specimens were produced using statically compacted EAF slag with 8 wt% water ad. The specimens were then divided into two groups, each subjected to a different CO₂ curing regime: accelerated curing (ACC) and supercritical curing (SCC). Samples were evaluated through compressive strength tests, TGA, XRD, SEM-EDX, and MIP analyses. The results demonstrated that supercritical curing (SCC) produced a more homogenous carbonation, a greater decrease in porosity, and improved mechanical properties. Thus, this study highlights the benefits of using supercritical curing to achieve higher mechanical properties due to more homogeneous curing across the samples' entire volume. Additionally, the EAF slag binders exhibited favourable binding properties without strict control of particle size distribution, facilitating application in the construction sector while contributing to waste circularity by reducing landfill disposal of EAFS and supporting the development of waste circularity and CO₂ sequestration through mineralisation in carbonated materials.

本文研究了CO2压力对电弧炉（EAF）炉渣粘结剂碳化硬化的影响。采用8 wt%的水和静压电炉炉渣制备了10个试样。然后将样品分为两组，每组都进行不同的CO2固化制度：加速固化（ACC）和超临界固化（SCC）。样品通过抗压强度测试、TGA、XRD、SEM-EDX和MIP分析进行评估。结果表明，超临界固化（SCC）产生了更均匀的碳化，孔隙率更低，力学性能得到改善。因此，这项研究强调了使用超临界固化的好处，因为在样品的整个体积上更均匀的固化，从而获得更高的机械性能。此外，在不严格控制粒径分布的情况下，电炉炉渣粘结剂表现出良好的粘结性能，有利于在建筑领域的应用，同时通过减少电炉炉渣的填埋处理，促进废物循环利用，并通过碳化材料的矿化促进废物循环利用和二氧化碳封存。

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引用次数: 0

Analysis of the composition, structure, and deterioration mechanisms of brick carvings in the Beijing Tianning Temple Pagoda 北京天宁寺宝塔砖雕的组成、结构及变质机理分析

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-05 DOI: 10.1016/j.cscm.2026.e05765

Yuhua Zhu , Guodong Qi , Yi Shen , Dong Xu , Shuai Han , Dongmin Wang

The Tianning Temple Pagoda in Beijing, a representative Liao Dynasty structure, features extensive brick carvings that exemplify the craftsmanship and aesthetic traditions of early Chinese masonry. After centuries of exposure to harsh climatic conditions and atmospheric pollution, the carvings have suffered severe deterioration, including salt efflorescence, delamination, and surface disintegration. To elucidate their material characteristics and deterioration mechanisms, this study employed multiple analytical methods—XRF, XRD, FTIR, TG-DTG, SEM-EDS, PLM, and IC—to investigate the composition, microstructure, and salt contamination of both the brick carvings and their lime-based binding materials. Results show that the bricks were made from high-silica–alumina clay (SiO₂ + Al₂O₃ + Fe₂O₃ > 70 %) fired above 1000 °C, with quartz, feldspar, and clay minerals as the main phases. The lime binder has fully carbonated into calcite (CaCO₃), providing structural adhesion between brick units. However, the brick matrix exhibits a loose and porous microstructure, which facilitates the migration and crystallization of soluble salts such as sulfates, nitrates, and chlorides. Ion chromatography indicates that the surface layers contain significantly higher concentrations of SO₄²⁻, NO₃⁻, and Cl⁻ compared with the interior, exceeding the critical thresholds defined in the WTA standard. These salts mainly originate from the long-term deposition of SO₂ and NOₓ emitted by nearby industrial sources, which, through acid-rain processes, react with silicate and feldspar minerals to form soluble sulfate and nitrate salts. Repeated wet–dry and temperature cycles promote salt crystallization and generate crystallization pressure, leading to flaking, granular disintegration, and loss of carved details. The study clarifies the physicochemical mechanisms responsible for the deterioration of Liao Dynasty brick carvings and provides a scientific basis for conservation strategies targeting salt weathering under polluted urban environments.

北京的天宁寺塔是辽代的代表性建筑，以大量的砖雕为特色，体现了中国早期砖石的工艺和美学传统。经过几个世纪的恶劣气候条件和大气污染，这些雕刻遭受了严重的破坏，包括盐花、分层和表面崩解。为了阐明其材料特性和变质机理，本研究采用xrf、XRD、FTIR、TG-DTG、SEM-EDS、PLM和ic等多种分析方法对砖雕及其石灰基结合材料的组成、微观结构和盐污染进行了研究。结果表明，砖是由高硅铝粘土（SiO₂+ Al₂O₃+ Fe₂O₃> 70 %）在1000℃以上烧制而成，主要相为石英、长石和粘土矿物。石灰粘合剂已经完全碳化成方解石（CaCO₃），为砖单元之间提供结构粘合。然而，砖基体表现出松散和多孔的微观结构，这有利于可溶性盐（如硫酸盐、硝酸盐和氯化物）的迁移和结晶。离子色谱法表明，与内部相比，表层含有明显更高浓度的SO₄²⁻、NO₃⁻和Cl⁻，超过了WTA标准中定义的临界阈值。这些盐主要来源于附近工业源排放的so2和NOₓ的长期沉积，它们通过酸雨过程与硅酸盐和长石矿物反应形成可溶性硫酸盐和硝酸盐。反复的干湿循环和温度循环促进盐结晶，产生结晶压力，导致剥落、颗粒崩解、雕刻细节丢失。本研究阐明了辽代砖雕变质的理化机制，为城市污染环境下针对盐风化的保护策略提供了科学依据。

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引用次数: 0