Cement and Concrete Research最新文献_第4页

The role of carbonate anions and early-formed phases on the efficiency of PCE in alkali-activated slag 碱渣中碳酸盐阴离子和早期形成相对PCE效率的影响

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-20 DOI: 10.1016/j.cemconres.2025.108122

Yuliang Wang, Shengnan Sha, Hailong Ye

The mechanism responsible for the reduced dispersing efficiency of polycarboxylate ether (PCE) superplasticizers in carbonate-activated slag system (AAS) remains controversial and ambiguous, particularly regarding the roles of carbonate anions and early-formed phases. This study systematically evaluated the fluidity and adsorption behavior of PCE in K₂CO₃-activated slag with varying alkali modulus and in CaO-K₂CO₃-activated slag. Results show that in K₂CO₃-activated slag systems, the inefficiency of PCE at low dosages (≤ 1 mg/g binder) is primarily due to its preferential adsorption onto early-formed calcium carbonate phases. At higher dosages (> 1 mg/g), both competitive adsorption by CO₃²⁻ ions and conformational collapse of PCE macromolecules dominate its reduced dispersing performance. In CaO–K₂CO₃-activated systems, early-formed calcium carbonate phases still consume part of the PCE at low dosages (≤ 4 mg/g). However, CaO reduces CO₃²⁻ ion concentration, weakening competitive adsorption and improving PCE dispersing efficiency compared to K₂CO₃-activated systems.

聚羧酸酯醚（PCE）高效减水剂在碳酸盐-活性渣体系（AAS）中分散效率降低的机理仍然存在争议和不明确，特别是关于碳酸盐阴离子和早期形成相的作用。研究系统地评价了PCE在不同碱模量的K₂CO₃活性渣和CaO-K₂CO₃活性渣中的流动性和吸附行为。结果表明，在K₂CO₃活性渣体系中，低剂量（≤1 mg/g粘结剂）PCE的低效率主要是由于其优先吸附在早期形成的碳酸钙相上。在较高剂量（1 mg/g）下，CO₃2−离子的竞争性吸附和PCE大分子的构象崩溃是其分散性能降低的主要原因。在CaO-K₂CO₃活化的系统中，早期形成的碳酸钙相仍然以低剂量（≤4mg /g）消耗部分PCE。然而，与K₂CO₃活化体系相比，CaO降低了CO₃2−离子浓度，削弱了竞争吸附，提高了PCE的分散效率。

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引用次数: 0

Impedance and electrical conductivity of C-S-H C-S-H的阻抗和电导率

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-20 DOI: 10.1016/j.cemconres.2025.108123

Tulio Honorio , Walter Batista Bonfim , Oswaldo Cascudo

The impedance and complex electrical conductivity of C-S-H have not been directly measured, even though electromagnetic measurements are a key non-destructive technique for probing cement systems. Here, we evaluate the frequency-dependent electrical conductivity of C-S-H using molecular dynamics simulations for the first time. The effect of nanopore size is assessed for pores spanning the interlayer to the gel range, showing that interlayer conductivity is governed by subdiffusive ion dynamics while Fickean dynamics drives gel pores behavior. Ionic self-correlations dominate the conductivity, while water–ion and solid–ion contributions are smaller but non-negligible. By combining molecular dynamics with mean-field homogenization, we obtain gel-scale estimates consistent with available data (i.e., with ratio between gel conductivity and pore solution conductivity on the order of 1/100). As with other transport properties, accounting for anisotropy and associated dimensionality loss is critical for understanding electrical conductivity bottom-up. Our results provide direct evaluation of the frequency-dependent conductivity of C-S-H, offering valuable input for multiscale modeling and for interpreting electromagnetic measurements of cementitious materials.

尽管电磁测量是探测水泥体系的关键非破坏性技术，但C-S-H的阻抗和复杂电导率尚未直接测量。在这里，我们首次使用分子动力学模拟来评估C-S-H的频率依赖性电导率。纳米孔大小对层间至凝胶范围孔隙的影响进行了评估，表明层间电导率受亚扩散离子动力学控制，而Fickean动力学驱动凝胶孔隙行为。离子自相关性主导电导率，而水离子和固体离子的贡献较小，但不可忽略。通过将分子动力学与平均场均质化相结合，我们获得了与现有数据一致的凝胶尺度估计（即凝胶电导率与孔隙溶液电导率之比约为1/100）。与其他输运性质一样，考虑各向异性和相关的维度损失对于自下而上地理解电导率至关重要。我们的研究结果提供了C-S-H的频率相关电导率的直接评估，为多尺度建模和解释胶凝材料的电磁测量提供了有价值的输入。

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引用次数: 0

Sodium aluminate activated BOF steel slag: Impact of Al(OH)4− on reaction mechanism 铝酸钠活化转炉钢渣：Al(OH)4−对反应机理的影响

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-19 DOI: 10.1016/j.cemconres.2025.108116

Mengyu Zhu , Yuxuan Chen , S.R. van der Laan , Tao Liu , Qingliang Yu

The limited hydraulic reactivity of Basic Oxygen Furnace (BOF) slag, caused by its low-aluminum and high-iron composition, restricts its high-value applications. This study employs sodium aluminate (NaAlO₂, NA) as an activator, with a focus on the mechanistic role of Al(OH)₄⁻ in modulating the hydration pathways of belite in BOF slag. Systematic investigations of phase evolution, microstructural development, pore solution chemistry, and mechanical properties reveal that NA significantly enhances the early reactivity of belite and brownmillerite and promotes the formation of Si(Fe)-rich hydrogarnet and C(N)-A-S-H gels, enabling synergistic hydration between belite and brownmillerite at early ages. The NA-activated pastes develop a denser microstructure, exhibiting quadrupled early strength compared to the non-activated system. Crucially, the system demonstrates superior environmental performance, with heavy metal leaching concentrations consistently below regulatory thresholds. These findings elucidate the activation mechanisms of NA and propose a viable strategy for advanced BOF slag utilization.

碱性氧炉（BOF）炉渣由于其低铝高铁的成分，导致其水力反应性有限，制约了其高价值应用。本研究采用铝酸钠（NaAlO2， NA）作为活化剂，重点研究了Al(OH)4−在转炉炉渣中调节白石水化途径的机理。系统的相演化、微观结构发育、孔隙溶液化学和力学性能研究表明，NA显著增强了白橄榄石和褐粒石的早期反应活性，促进了富Si（Fe）水榴石和C(N) a - s - h凝胶的形成，使白橄榄石和褐粒石在早期发生协同水化作用。与未激活的体系相比，na激活的膏体具有更致密的微观结构，表现出四倍的早期强度。至关重要的是，该系统表现出优越的环保性能，重金属浸出浓度始终低于监管阈值。这些发现阐明了NA的活化机理，并为转炉炉渣的高级利用提出了可行的策略。

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引用次数: 0

Synergistic sulfate-alkaline activation of one-part volcanic pumice–cement binders: Mechanisms and microstructural evolution 单组分火山浮石-水泥粘结剂硫酸盐-碱协同活化：机理与微观结构演化

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-18 DOI: 10.1016/j.cemconres.2025.108103

Jesus López-Salas, J. Ivan Escalante-García

The synergistic activation of a novel one-part volcanic pumice-PC hybrid binder with a Na₂SO₄-Al₂(SO₄)₃-Ca(OH)₂ (NŜ-AŜ-CH) ternary system was elucidated using a suite of advanced characterization techniques. The reaction proceeds via two distinct pathways: a rapid sulfatic pathway, where Al₂(SO₄)₃ promotes ettringite (AFt) formation for early strength, and a primary alkaline pathway, where the Na₂SO₄-Ca(OH)₂ synergy generates in-situ NaOH, driving VP dissolution and C-(N)-A-S-H formation. This resulted in a nearly threefold increase in 1-day strength, with optimized binders reaching over 70 MPa at 90 days. Long-term analysis reveals the “dual role” of AS, as its persistent AFt provides microstructural reinforcement. This leads to a “composite strength mechanism,” a key finding where high strength is achieved even in systems with a less polymerized silicate network (low Mean Chain Length). The NS-CH synergy, in contrast, is the primary driver for high polymerization, informing a new model for designing sustainable binders.

采用一系列先进的表征技术，研究了一种新型的单组分火山浮石- pc复合粘结剂与Na₂SO₄-Al₂（SO₄）₃-Ca（OH）₂（NŜ-AŜ-CH）三元体系的协同活化作用。反应通过两种不同的途径进行：快速硫酸途径，其中Al₂（SO₄）₃促进钙矾石（AFt）的形成以获得早期强度；初级碱性途径，其中Na₂SO₄- ca (OH) 2协同作用产生原位NaOH，驱动VP溶解和C-(N) a -s - h的形成。这使得1天的强度增加了近3倍，优化后的粘合剂在90天的强度超过70 MPa。长期分析揭示了AS的“双重作用”，因为其持久的AFt提供了微观结构的强化。这导致了“复合强度机制”，这是一个关键的发现，即使在具有较少聚合硅酸盐网络（低平均链长）的系统中也能实现高强度。相比之下，NS-CH协同作用是高聚合的主要驱动因素，为设计可持续粘合剂提供了新的模型。

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引用次数: 0

New insights into dynamic evolution of colloidal network structure during early-age hardening of cementitious materials 胶凝材料早期硬化过程中胶体网络结构动态演化的新认识

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-18 DOI: 10.1016/j.cemconres.2025.108120

Hengrui Liu , Kaiyin Zhao , Shipeng Zhang , Hanghua Zhang , Shuangshuang Liu , Lucen Hao , Hongyan Ma , Kamal Khayat , Chi Sun Poon

The evolution of microstructure in cementitious materials during their transition from fluid to solid state plays a critical role in determining their ultimate mechanical strength and overall performance. This hydration stage primarily involves a dynamic densification process occurring within the colloidal network. However, the field of cement-based materials currently lacks a comprehensive theoretical framework and associated parameters capable of effectively characterizing the specific structural regions within this network. In this study, we propose an Improved Particle Linkage (IPL) theory for describing the strength, types, and quantities of particle linkages within colloidal network. The IPL theory classifies the internal network structure into three distinct regions, namely the α_weak, β_strong and γ_inherent. The γ_inherent and β_strong region predominantly influence the strength of the colloidal network at the initial and later hydration stages, respectively, whereas the α_weak region contributes steadily to the network strength across all hydration stages. Furthermore, the progressive intensification of the β_strong region during hydration is identified as the principal driving factor for microstructural evolution, leading to a critical transition point in fresh properties. Additionally, a novel parameter, termed the network hydration index (ξ), to quantitatively characterize the overall degree of hydration within the colloidal network is establishment.

胶凝材料从流体状态向固体状态转变过程中微观结构的演变对其极限力学强度和综合性能起着至关重要的作用。这个水化阶段主要涉及发生在胶体网络内的动态致密化过程。然而，水泥基材料领域目前缺乏能够有效表征该网络中特定结构区域的综合理论框架和相关参数。在这项研究中，我们提出了一种改进的粒子连接（IPL）理论来描述胶体网络中粒子连接的强度、类型和数量。IPL理论将内部网络结构分为三个不同的区域，即α弱、β强和γ固有。γ固有区和β强区分别主要影响水化初期和后期的胶体网络强度，而α弱区则稳定影响所有水化阶段的胶体网络强度。此外，在水化过程中β强区逐渐增强被认为是微观结构演变的主要驱动因素，导致了新鲜性能的关键转变点。此外，建立了一个新的参数，称为网络水化指数（ξ），以定量表征胶体网络内的水化总体程度。

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引用次数: 0

The role of clinker mineralogy in cement properties: An analysis using statistical mixture design 熟料矿物学在水泥性能中的作用：使用统计混合料设计的分析

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-17 DOI: 10.1016/j.cemconres.2025.108102

José S. Andrade Neto , Ivo C. Carvalho , Henrique A. Santana , Paulo Matos , Ana Paula Kirchheim

This study applied a statistical mixture design to assess the influence of clinker composition and mineralogy on early hydration and strength. Twenty-one mixtures were prepared using six industrial clinkers with distinct mineralogical characteristics. Hydration was assessed using isothermal calorimetry, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Compressive strength was measured at 1 and 28 days. The results revealed that alkali content (Na₂Oeq) was the most influential parameter controlling cumulative heat release up to 72 h. Interestingly, no clear correlation was observed between bulk phase content and early strength, emphasizing that mineralogical composition alone is not a reliable predictor of performance. These findings underscore the complexity of hydration mechanisms and highlight the importance of controlling clinker chemistry and mineralogy. Moreover, statistical mixture design proved an effective tool for exploring multivariate interactions governing hydration and strength development.

本研究采用统计混合设计来评估熟料组成和矿物学对早期水化和强度的影响。采用矿物学特征不同的6种工业熟料配制了21种混合料。采用等温量热法、x射线衍射（XRD）和热重分析（TGA）对水合作用进行了评价。在第1天和第28天测量抗压强度。结果表明，碱含量（Na2Oeq）是控制72 h累积放热的最重要参数。有趣的是，体相含量与早期强度之间没有明显的相关性，强调矿物成分本身并不是性能的可靠预测因子。这些发现强调了水化机制的复杂性，并强调了控制熟料化学和矿物学的重要性。此外，统计混合设计被证明是探索控制水化和强度发展的多元相互作用的有效工具。

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引用次数: 0

Quantitative characterization of interfacial enhancement in microfiber-reinforced recycled cementitious composites after carbonation using nanoindentation combined with 4D CT 纳米压痕结合4D CT定量表征微纤维增强再生胶凝复合材料碳化后界面增强

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-17 DOI: 10.1016/j.cemconres.2025.108115

Changqing Wang , Yuelan Lu , Zhiming Ma

This study systematically explores the interfacial transition zone (ITZ) strengthening mechanisms in microfiber-reinforced recycled cementitious composites (MF-RCC) under carbonation treatment, primarily through quantitative nanoindentation mapping combined with supportive 4D CT imaging. Nanoindentation was innovatively adopted to quantify ITZ enhancement, revealing significant increases of approximately 42 % in local hardness and 48 % in elastic modulus after carbonation. A statistical deconvolution model was established to interpret the nanoindentation data, clearly showing a shift toward higher hardness and reduced variability (homogeneity improved by approximately 35 %) in the carbonated specimens. Complementary 4D CT characterization validated these findings, indicating a noticeable reduction of porosity by approximately 40 %, thus supporting the mechanical densification of the ITZ. The integrated nanoindentation and statistical modeling results highlight carbonation combined with microfiber reinforcement as an effective approach to optimize interfacial properties and mechanical stability, providing quantitative insights for the sustainable design of recycled cementitious materials.

本研究系统探讨了碳化处理下微纤维增强再生胶凝复合材料（MF-RCC）的界面过渡区（ITZ）强化机制，主要通过定量纳米压痕成像结合支持性4D CT成像。创新地采用纳米压痕来量化ITZ增强，显示碳化后局部硬度显著提高约42%，弹性模量显著提高48%。建立了一个统计反褶积模型来解释纳米压痕数据，清楚地显示碳化样品向更高的硬度和更少的可变性（均匀性提高了约35%）转变。补充4D CT表征证实了这些发现，表明孔隙度显著降低了约40%，从而支持了ITZ的机械致密化。综合纳米压痕和统计建模结果表明，碳化结合超细纤维增强是优化界面性能和机械稳定性的有效方法，为再生胶凝材料的可持续设计提供了定量见解。

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引用次数: 0

Revisiting MgO reactivity: The critical role of mesopores and surface defects of particles 重述氧化镁的反应性：颗粒的介孔和表面缺陷的关键作用

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-16 DOI: 10.1016/j.cemconres.2025.108118

Jiaze Wang , Hangjie Zhou , Yufeng Song , Chengzhuo Xie , Cise Unluer , Shaoqin Ruan

The reactivity of magnesia (MgO) is a critical determinant of the performance of magnesia-based cements. While conventional theory correlates MgO reactivity primarily with specific surface area (SSA), this study utilizes a multi-technique approach to reveal a more complex dependency governed by the interplay between pore structure and surface defect density. Through controlled synthesis of MgO from calcinating Mg(OH)₂ at 400, 500, and 600 °C for 2 h, we demonstrate that the sample calcined at 500 °C (S5–2) exhibits the highest reactivity, despite possessing a lower SSA than the 400 °C counterpart. A multi-technique approach, combining TEM, in-situ XRD, BET, LF-NMR, XPS, PL, and ESR analyses, reveals that this enhanced reactivity is strongly correlated with a synergistic combination of a favorable mesoporous architecture (~10–100 nm), hypothesized to facilitate efficient water transport, and a maximized concentration of surface oxygen vacancies, which are believed to promote hydrolysis. This perspective supplements existing theory and provides guidance for designing magnesia cements with stable and reproducible performance, addressing one of the major challenges in this field.

氧化镁（MgO）的反应性是决定镁基水泥性能的关键因素。虽然传统理论将MgO反应性主要与比表面积（SSA）联系起来，但本研究利用多技术方法揭示了由孔隙结构和表面缺陷密度之间的相互作用决定的更复杂的依赖关系。通过对Mg(OH)2在400、500和600℃下煅烧2小时合成MgO的控制，我们发现在500℃（S5-2）下煅烧的样品表现出最高的反应活性，尽管其SSA低于400℃的样品。结合TEM、原位XRD、BET、rf - nmr、XPS、PL和ESR分析的多技术方法表明，这种增强的反应性与有利的介孔结构（~ 10-100 nm）（假设有助于有效的水输送）和最大的表面氧空位浓度（被认为有助于促进水解）的协同作用密切相关。这一观点补充了现有理论，为设计性能稳定、可重复的镁质水泥提供了指导，解决了该领域的主要挑战之一。

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引用次数: 0

Evolution of hydration in cement blends with incorporation of activated low-kaolinite clays: Insights into the preferred aluminum uptake by C-(A)-S-H 掺入活化低高岭石粘土的水泥混合物中水化的演变：C-(A)- s - h对铝的首选吸收的见解

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-12 DOI: 10.1016/j.cemconres.2025.108086

Amrita Hazarika , Liming Huang , Joao Figueira , Arezou Babaahmadi

Despite their global abundance, heterogenous clays are often excluded from SCM applications, due to their limited pozzolanicity. This study investigates hydration evolution, particularly aluminum uptake pathways, in statistically designed cement blends incorporating thermo-mechanochemically activated low-kaolinite clays.

Despite kaolinite contents below 40%, a 30% binary blend achieved 110% and 125% of OPC strength at 7 and 56 days, respectively, while reducing total porosity by 42% at 56 days. ²⁹Si NMR indicated an increase in silicate chain length in C-(A)-S-H, correlating with pore structure refinement and strength gain in 56 days of hydration. ²⁷Al NMR revealed a preferential incorporation of aluminum into C-(A)-S-H rather than AFm phases. This behavior is attributed to the lower alumina availability in the system compared to LC3 blends, suggesting that in such environments, C-(A)-S-H becomes the dominant host phase for aluminum. This incorporation pathway reduces the Al availability for carbonate-AFm formation, limiting the synergy typically observed in LC3 systems with added limestone.

尽管非均质粘土在全球范围内丰富，但由于其有限的火山喷发性，它们通常被排除在SCM应用之外。本研究调查了统计设计的水泥混合物中水化演化，特别是铝的吸收途径，这些水泥混合物含有热机械化学活化的低高岭石粘土。尽管高岭石含量低于40%，但30%的二元共混物在第7天和第56天分别达到了OPC强度的110%和125%，同时在第56天将总孔隙度降低了42%。29Si核磁共振表明，C-(A)- s - h中的硅酸盐链长增加，这与水化56 d后孔隙结构的细化和强度的增加有关。27Al核磁共振显示铝优先掺入C-(a)- s - h相，而不是AFm相。这种行为归因于与LC3混合物相比，体系中氧化铝的可用性较低，这表明在这种环境下，C-(A)- s - h成为铝的主要宿主相。这种掺入途径降低了Al对碳酸盐- afm形成的可用性，限制了在添加石灰石的LC3体系中通常观察到的协同作用。

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引用次数: 0

In situ reaction-strengthening of ice-templated porous geopolymers for high anisotropy and robustness 高各向异性和坚固性的冰模板多孔地聚合物的原位反应强化

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research

Pub Date : 2025-12-11 DOI: 10.1016/j.cemconres.2025.108104

Fangxian Li , Chaofeng Zhang , Qiang Yu , Li Zheng , Jiangxiong Wei , Qijun Yu

Ice-templating enables ordered porous architectures but fails in geopolymers due to suppressed reactions at cryogenic temperatures and water loss during sublimation, yielding fragile scaffolds. We propose an in situ reaction strategy that converts ice from a passive porogen into a controlled-release solvent. By introducing a staged low-temperature polymerization (−5 °C to +5 °C) before sublimation, the gradually melting ice initiates geopolymerization in situ, forming a C-(A)-S-H gel that strengthens pore walls. This approach prevents collapse, ensures faithful ice-template replication, and yields porous geopolymers with compressive strength above 6.5 MPa, far exceeding conventional counterparts (<2 MPa). The materials exhibit pronounced anisotropy (σ_z/σ_y > 3.6) and well-defined lamellar pores. This strategy addresses a key limitation in ice-templating and opens pathways for fabricating high-performance porous materials from water-dependent reactive systems.

冰模板可以实现有序的多孔结构，但由于在低温下抑制反应和升华过程中的水分损失，在地聚合物中失败，产生脆弱的支架。我们提出了一种原位反应策略，将冰从被动多孔介质转化为控释溶剂。通过在升华前引入阶段低温聚合（- 5°C至+5°C），逐渐融化的冰在原位引发地聚合，形成C-(a)- s - h凝胶，增强孔壁。这种方法可以防止坍塌，确保忠实的冰模板复制，并产生抗压强度超过6.5 MPa的多孔地聚合物，远远超过传统的同类产品（2 MPa）。材料具有明显的各向异性（σz/σy > 3.6）和清晰的层状孔隙。该策略解决了冰模板的一个关键限制，并为利用依赖水的反应体系制造高性能多孔材料开辟了途径。

引用次数: 0