Journal of Advanced Concrete Technology最新文献_第4页

Investigation on Preparation and Application in Concrete of Physically Modified Fly Ash 物理改性粉煤灰的制备及在混凝土中的应用研究

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2024-02-17 DOI: 10.3151/jact.22.77

Sun Zhisheng, Zhu Wenshang, Ma Zhaomo, Wang Xingqin, Yang Zhongmao, Zou Chunye, Huang Qin, Feng Xianxu, Rao Zhengtang

{"title":"Investigation on Preparation and Application in Concrete of Physically Modified Fly Ash","authors":"Sun Zhisheng, Zhu Wenshang, Ma Zhaomo, Wang Xingqin, Yang Zhongmao, Zou Chunye, Huang Qin, Feng Xianxu, Rao Zhengtang","doi":"10.3151/jact.22.77","DOIUrl":"https://doi.org/10.3151/jact.22.77","url":null,"abstract":"Raw fly ash (RFA) was modified by a self-developed new dry energy-saving vertical grinding mill. This was beneficial to improve the particle morphology and distribution of RFA and enhanced its practical applicability in cement and concrete. The physical modification mechanism of RFA was elucidated by simulating the grinding process, and the physical properties and the application performance of modified fly ash (MFA) were characterized. The results demonstrated that the new grinder can effectively realize the physical modification of RFA and significantly improve its properties because the porous structure and the intactness of glass beads of RFA are preserved without being destroyed. The fineness of MFA was improved to the standard of Class I or II fly ash, the 28 d strength activity index of which was increased by 7% to 17%. The fluidity of mortar was also improved by 15 to 34 mm. In addition, the water requirement ratio can be significantly reduced when MFA is used to prepare C30 and C45 concrete. The 28 d strength of concrete with 50% content of MFA was increased by 23.76% and 15.84%, respectively. These results suggest that the grinding process studied here is a novel method for improving the performance of MFA.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139901977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of Post-installed Headed Bars Embedded into Grouted Holes with Enlarged Ends 将后安装封头钢筋嵌入扩大端部的灌浆孔中的发展情况

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2024-01-24 DOI: 10.3151/jact.22.62

Hassane Ousalem, Gin Horiuchi, Akitoshi Hamada, Hiroto Takatsu, Yuki Idosako, Hiroyuki Masuda, Yuki Hiroshima

引用次数: 0

Experimental Study of Bonding Performance of Post-installed Rebar Anchors under Unilateral Pressure 后安装钢筋锚固件在单侧压力下的粘结性能实验研究

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2024-01-23 DOI: 10.3151/jact.22.47

Ning-yu Zhao, Ailin Yang, Hao Liu, Yi Song, Haifei Jiang

{"title":"Experimental Study of Bonding Performance of Post-installed Rebar Anchors under Unilateral Pressure","authors":"Ning-yu Zhao, Ailin Yang, Hao Liu, Yi Song, Haifei Jiang","doi":"10.3151/jact.22.47","DOIUrl":"https://doi.org/10.3151/jact.22.47","url":null,"abstract":"Post-installed rebar (PIR) is extensively utilized for rehabilitating, strengthening, and retrofitting existing concrete structures, and its anchorage design greatly concerns the failure mode and tensile behavior. PIR anchored in joints or columns generally suffers pressures normal to its anchorage section in one direction, and PIR's failure mode and tensile behavior can be greatly affected. However, limited research on the unilateral pressure effect for PIR has been conducted, with remaining uncertainties on applications and designs for PIR. Thus, this paper carried out the pull-out tests of 38 specimens with various anchorage conditions (20 unilateral pressure specimens, 14 no-lateral pressure specimens, and four bilateral pressure specimens) to investigate the bond behavior for PIR subjected to unilateral pressure. Besides, the effects of concrete strength, rebar diameter, and anchorage length on PIR under unilateral pressure were also considered in the tests. The test results showed that the no-lateral pressure specimens split in the concrete and adhesive layer. In contrast, the unilateral and bilateral pressure specimens occurred two typical failures [adhesive-rebar (A-R) interface failure and adhesive fracture failure]. In addition, the interfacial damage and cracking pattern were discussed in detail. Then, the bond strength and bond slip of specimens were investigated. The result showed that the bond strength under unilateral pressure was greater than that under no-lateral pressure but less than that under bilateral pressure, and there was no obvious change in bond strength while the unilateral pressure increased. Regarding bond slip, it was found that the bond slip increased with the bond strength. This paper performed an experimental investigation on failure modes and cracking patterns for PIR under unilateral pressure. It analyzed the unilateral pressure effect on the bond performance for PIR, raising the safety considerations about PIR applications in load-bearing structures.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139552139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multi-exponential Inversion of the Relaxometry Data of Low-field Nuclear Magnetic Resonance for Cement-based Materials 水泥基材料低场核磁共振弛豫测量数据的多指数反演

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2024-01-20 DOI: 10.3151/jact.22.33

Xiaoyu Zhang, Chunsheng Zhou, Jing Qiao, Le Li, Lizhi Xiao

{"title":"Multi-exponential Inversion of the Relaxometry Data of Low-field Nuclear Magnetic Resonance for Cement-based Materials","authors":"Xiaoyu Zhang, Chunsheng Zhou, Jing Qiao, Le Li, Lizhi Xiao","doi":"10.3151/jact.22.33","DOIUrl":"https://doi.org/10.3151/jact.22.33","url":null,"abstract":"Low-field Nuclear Magnetic Resonance (LF-NMR) technique has been attracting increasing concern in nondestructively characterising cement-based materials (CBMs), whose nanoscale pore structure are sensitive to water removal. In order to achieve the multi-exponential inversion of relaxometry data preferred by the interpretation on local pore structure of CBMs, an algorithm incorporating L1 regularisation with capability of yielding sparse solution is developed with the aids of Interior-Point method and various principles for optimising the regularisation parameter. Numerical analyses on representative cases show that, the proposed algorithm equipped with the Morozov discrepancy principle is capable of resolving all artificially designed exponential components of various intensities with satisfactory accuracy and precision, even at relatively low signal-to-noise ratio. When applying to resolve the relaxometry data obtained on a cement paste, the algorithm is good at characterising its pore structure with clear significance and capturing its detailed evolution during curing under hot water with good precision.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139508679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of Temperature on the Early-age Hydration and Setting Behaviour of Mixes Containing GGBS 温度对含 GGBS 混合料早期水化和凝结行为的影响

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2024-01-12 DOI: 10.3151/jact.22.14

Fragkoulis Kanavaris, Marios Soutsos, Jian-Fei Chen

{"title":"Effect of Temperature on the Early-age Hydration and Setting Behaviour of Mixes Containing GGBS","authors":"Fragkoulis Kanavaris, Marios Soutsos, Jian-Fei Chen","doi":"10.3151/jact.22.14","DOIUrl":"https://doi.org/10.3151/jact.22.14","url":null,"abstract":"Over the past years there has been an increasing trend to use supplementary cementitious materials in concrete to improve its sustainability credentials and durability properties. Perhaps amongst the most popular supplementary cementitious materials is ground granulated blast-furnace slag (GGBS). While the hydration and setting characteristics of mixes with GGBS cured under standard conditions (20°C) has been adequately investigated, the effect of temperature on heat of hydration and setting and the interrelation of these properties has not been evaluated for GGBS containing mixes. In this study, the heat of hydration and setting behaviour of mixes with various levels of GGBS (0, 20, 35, 50 and 70%) cured under elevated temperatures (20, 30, 40, 50 and 60°C) is determined. Elevated curing temperature accelerates the hydration reactions and can significantly reduce the setting time of GGBS-containing mixes. The investigation of heat of hydration at very early ages, can provide an indication of the initial and final setting times of cementitious mixes. The “apparent” activation energy used to characterise temperature sensitivity of cementitious systems, is calculated based on heat of hydration and setting time measurements. It was found that the “apparent” activation energy increases with GGBS content for both heat of hydration and setting behaviour. The value of “apparent” activation energy differs significantly depending on the material property that is considered, such as compressive strength, heat of hydration or setting time.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139464352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shear Behaviour of RC Beams Strengthened using CFRP Grid-ECC/PMM Matrix Composites: An Experimental and Numerical Investigation 使用 CFRP 网格-ECC/PMM 矩阵复合材料加固的 RC 梁的剪切行为：实验与数值研究

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2024-01-07 DOI: 10.3151/jact.22.1

Xu Yang, Jun-Qi Huang

{"title":"Shear Behaviour of RC Beams Strengthened using CFRP Grid-ECC/PMM Matrix Composites: An Experimental and Numerical Investigation","authors":"Xu Yang, Jun-Qi Huang","doi":"10.3151/jact.22.1","DOIUrl":"https://doi.org/10.3151/jact.22.1","url":null,"abstract":"In recent advancements, a novel strengthening approach employing engineered cementitious composites (ECC) and fibre-reinforced polymer (FRP) materials has emerged. This method integrates ECC as the matrix, carbon fibre-reinforced polymer (CFRP) grid as the internal strengthening component, and epoxy resin for bonding the overlay to the concrete substrate. This study conducted tests on four reinforced concrete (RC) beams under a four-point load configuration. One beam served as an un-strengthened control specimen, while three were subjected to different shear strengthening methods: polymer-modified mortar (PMM), ECC, and CFRP grid-reinforced ECC matrix composites layer (FGREM). The investigation covered failure modes, load-deformation relationships, and load-strain relationships. Finite element (FE) analysis was employed to reproduce the test results. Key findings include the ability of ECC as a matrix to substantially reduce concentrated interfacial bond stresses, preventing debonding failure. The FGREM-strengthened specimen exhibited a failure mode characterized by side concrete cover separation, resulting in a notable 124% enhancement in shear resistance. The proposed FE model, incorporating interfacial behaviour, accurately simulated the performance of all specimens.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139373956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probabilistic Service Life Prediction of Alkali Activated Concretes Exposed to Chloride Induced Corrosion 暴露于氯化物诱导腐蚀的碱活性混凝土使用寿命概率预测

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2023-12-26 DOI: 10.3151/jact.21.1020

Tamara Janey Chidiac, Neven Ukrainczyk, Dale P. Prentice, John L. Provis

{"title":"Probabilistic Service Life Prediction of Alkali Activated Concretes Exposed to Chloride Induced Corrosion","authors":"Tamara Janey Chidiac, Neven Ukrainczyk, Dale P. Prentice, John L. Provis","doi":"10.3151/jact.21.1020","DOIUrl":"https://doi.org/10.3151/jact.21.1020","url":null,"abstract":"In this study, the well-established service life design code defined in fib Bulletin 34 is adapted to predict the time to initiation of reinforcement corrosion in alkali-activated concretes submerged in marine conditions. The model approach is based on the probabilistic calculation of the time needed for a critical concentration of chloride ions, migrating from the external environment towards the rebar, to accumulate at the surface of the steel reinforcement and initiate the corrosion reaction. The information required to define the parameters of the model is derived from literature data, relating the concrete mix designs with accelerated laboratory test results. The findings indicate that alkali-activated concretes with high calcium content can exhibit promising characteristics as a construction material applied for structural application in chloride-rich corrosive environments. The probabilistic approach adopted in this model provides the opportunity to assess the influence of variability in mineralogical composition and reactivity of the precursors with the alkaline activating solution, that influence the chemical evolution and microstructure of the binder matrix. The predicted service life is quite sensitive to these factors, with very high service lives predicted for some alkali-activated concretes but rather short service lives predicted for others, and this must be incorporated into any engineering assessment of future material performance.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139052543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of Lime-Based Expansion Material and Freeze-Thaw Cycles on Air-Void Blockage in Concrete 石灰基膨胀材料和冻融循环对混凝土气泡堵塞的影响

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2023-12-19 DOI: 10.3151/jact.21.1008

Hidehiko Ogata, Momona Otsuka, Masahiro Hyodo, Haruka Ikadatsu

{"title":"Effects of Lime-Based Expansion Material and Freeze-Thaw Cycles on Air-Void Blockage in Concrete","authors":"Hidehiko Ogata, Momona Otsuka, Masahiro Hyodo, Haruka Ikadatsu","doi":"10.3151/jact.21.1008","DOIUrl":"https://doi.org/10.3151/jact.21.1008","url":null,"abstract":"Air voids in concrete are sometimes observed to be blocked by white precipitates. In this study, the authors conducted freeze-thaw tests on concrete mixed with lime-based expansion material and then performed microscopic observations using scanning electron microscopy, elemental analysis using energy-dispersive X-ray spectroscopy. The size distributions of air voids in the concrete during the curing period (28 days after placement) and before, during, and after the tests were also measured in order to investigate the effects of the expansion material on air-void blockage as well as the underlying processes. During the curing period, no air-void blockage was observed. However, as the concrete aged, precipitates formed on the inner surfaces of the air voids. During the freeze-thaw tests, the number of air voids with diameters of ≤0.15 mm decreased, and the air-void spacing factor increased as the relative dynamic modulus of elasticity decreased. It was found that freeze-thaw cycles caused calcium-based precipitates to form inside the air voids of concrete mixed-with lime-based expansion material, and that the air voids became blocked.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138715220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Influences and Effect Mechanism of Low Temperature Curing on the Performances of Basic Magnesium Sulfate Cement 低温固化对碱式硫酸镁水泥性能的影响及作用机制

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2023-12-13 DOI: 10.3151/jact.21.995

Keyue Fang, Chengyou Wu, Hongdu Chen

{"title":"The Influences and Effect Mechanism of Low Temperature Curing on the Performances of Basic Magnesium Sulfate Cement","authors":"Keyue Fang, Chengyou Wu, Hongdu Chen","doi":"10.3151/jact.21.995","DOIUrl":"https://doi.org/10.3151/jact.21.995","url":null,"abstract":"Due to lightweight, high-strength, and high toughness properties, Basic magnesium sulfate cement (BMSC) can be widely used in producing various structural and decorative products. Most current research only focuses on the performance of BMSC under room temperature. However, low temperature environments may have a serious impact on the performance of BMSC, such as during cold seasons or in salt lake cold regions with abundant magnesium resources, so the performance of BMSC in low temperature environment needs to be explored to expand its application. This study investigated the influence of different low temperatures (−5 to 20°C) on the compressive strength and water resistance of BMSC cement. The phase composition, microstructure and pore structure of BMSC has been analyzed using XRD, QXRD, TG/DTA, SEM, BSEM/EDS Mapping and MIP. The Results indicate that the low hydration rate, precipitation of magnesium sulfate, increase in porosity and decrease in 517 phase content are the main reasons for the low strength of BMSC under low temperature curing. Although hardened BMSCs cured at low temperatures can continue to hydrate in water to form strength phases, corrosion and cracking may occur. Replacing light burned magnesite with high active magnesium oxide can significantly improve the mechanical properties of low temperature cured BMSC. However, low temperatures reduced the crystallinity of the 517 phase, thereby increasing its water solubility and lead to poor water resistance of BMSC.\u0000","PeriodicalId":14868,"journal":{"name":"Journal of Advanced Concrete Technology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138687015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydration Mechanism of Portland and Calcium Sulphoaluminate Cementitious Material 硅酸盐和硫铝酸钙水泥基材料的水化机理

IF 2 4区工程技术

Journal of Advanced Concrete Technology Pub Date : 2023-12-13 DOI: 10.3151/jact.21.983

Jiahe Wang, Yanbin Tan, Huajian Li, Yongjiang Xie, Zhongwei Feng

引用次数: 0