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Gao, Peng (author), Chen, Yang (author), Huang, Haoliang (author), Qian, Zhiwei (author), Schlangen, E. (author), Wei, Jiangxiong (author), Yu, Qijun (author)Non-uniform stresses, strains and microcracking of the concretes with three coarse aggregate sizes (5–10 mm, 10–16 mm, 16–20 mm) dried under 40% relative humidity (RH) for 60 days were quantified using digital image correlation and lattice fracture modelling. The influencing mechanism of coarse aggregate size on the drying-induced...journal article 2021
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Lu, T. (author), Li, Z. (author), Huang, H. (author)Shrinkage-induced cracking can impair the durability of concrete structures. In the past few decades, this topic has drawn more and more attention. Shrinkage of mortar and concrete is actually the result of the interaction between the shrinking cement paste and the non-shrinking aggregates. In recent years, different models that consider the...journal article 2021
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Li, Z. (author), Lu, T. (author), Liang, X. (author), Dong, H. (author), Ye, G. (author)This study aims to provide a better understanding of the autogenous shrinkage of slag and fly ash-based alkali-activated materials (AAMs) cured at ambient temperature. The main reaction products in AAMs pastes are C-A-S-H type gel and the reaction rate decreases when slag is partially replaced by fly ash. Due to the chemical shrinkage and the...journal article 2020
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Li, Z. (author), Wyrzykowski, Mateusz (author), Dong, H. (author), Granja, José (author), Azenha, Miguel (author), Lura, Pietro (author), Ye, G. (author)In this study, internal curing by superabsorbent polymers (SAP) is utilized to mitigate self-desiccation and autogenous shrinkage of alkali-activated slag (AAS) pastes. Absorption and desorption kinetics of SAP incorporated in AAS pastes were studied with X-ray tomography. Internal curing delayed the peak of the rate of heat liberation but...journal article 2020
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Lu, T. (author), Li, Z. (author), Huang, H. (author)In recent years more and more attention has been given to autogenous shrinkage due to the increasing use of high-performance concrete, which always contains supplementary materials. With the addition of supplementary materials-e.g., fly ash and blast furnace slag-internal relative humidity, chemical shrinkage and mechanical properties of...journal article 2020
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Lu, T. (author), Li, Z. (author), van Breugel, K. (author)In recent decades, several simulation models have been proposed to predict autogenous shrinkage of cementitious systems. In most of these models, however, only the elastic deformation caused by self-desiccation of the hydrating cement paste is considered. In fact, cement paste is not an ideal elastic material. Also the time-dependent...journal article 2020
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Li, Z. (author), Zhang, Shizhe (author), Liang, X. (author), Ye, G. (author)This study aims to investigate the cracking potential of alkali-activated slag (AAS) and alkali-activated slag-fly ash (AASF) concrete subjected to restrained autogenous shrinkage. Temperature Stress Testing Machine (TSTM) is utilized, for the first time, to monitor the stress evolution and to measure the cracking time of alkali-activated...journal article 2020
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Gao, Peng (author), Chen, Yang (author), Huang, Haoliang (author), Qian, Zhiwei (author), Schlangen, E. (author), Wei, Jiangxiong (author), Yu, Qijun (author)Concrete generally deforms and cracks in a non-uniform manner under drying-induced stress. This study used the lattice fracture model to simulate the drying-induced non-uniform deformations, stresses, and micro-crack propagation in concrete. Experiments were designed to validate the lattice fracture model, wherein the drying-induced non...journal article 2020
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Gao, Peng (author), Chen, Yang (author), Huang, Haoliang (author), Qian, Zhiwei (author), Schlangen, E. (author), Wei, Jiangxiong (author), Yu, Qijun (author)To assess the effect of relative humidity (RH) on drying-induced damage in concrete, the non-uniform strains and microcracks in concrete under different RH conditions were obtained using the digital image correlation (DIC) technique and lattice fracture model. The simulated non-uniform displacements were consistent with those captured using...journal article 2020
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Li, Z. (author), Yao, X. (author), Chen, Y. (author), Lu, T. (author), Ye, G. (author)Alkali-activated slag and fly ash (AASF) materials are emerging as promising alternatives to conventional Portland cement. Despite the superior mechanical properties of AASF materials, they are known to show large autogenous shrinkage, which hinders the wide application of these eco-friendly materials in infrastructure. To mitigate the...journal article 2020
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Li, Z. (author), Zhang, Shizhe (author), Liang, X. (author), Granja, José (author), Azenha, Miguel (author), Ye, G. (author)This study investigates the influences of internal curing on reducing the autogenous shrinkage of alkali-activated slag/fly ash (AASF) paste. The influences of internal curing with superabsorbent polymers (SAPs) on the reactions and microstructure of AASF paste are investigated. It is found that the SAPs absorb liquid mainly before the...journal article 2020
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Yalçinkaya, Ç. (author), Felekoglu, Burak (author), Yazici, Halit (author)Rheology and shrinkage are the key features that should be controlled to perform a successful casting process and obtain a durable ultra-high performance concrete (UHPC). It is anticipated that cast-in-situ applications of UHPC will increase in the near future, so the studies on early-age properties of UHPC have come into prominence. However,...journal article 2020
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Bouquet, G.C. (author)For the dimensioning of concrete structures it is customary to determine the forces and stresses occurring in construction elements on the basis of the prescribed loads. In an iterative process, the final dimensions of the elements and reinforcement are then determined. This process becomes less simple if not only the external loads, but also...doctoral thesis 2019
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Lu, T. (author)Concrete is a brittle composite material that easily fractures under tension. Due to the fact that the early-age deformation of the concrete member is restrained by adjoining structures, cracking can occur throughout the concrete prior to application of any load. The cracks would provide preferential access for aggressive agents penetrating in...doctoral thesis 2019
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Li, Z. (author), Nedeljković, Marija (author), Chen, B. (author), Ye, G. (author)This study investigates the effectiveness of metakaolin (MK)in mitigating the autogenous shrinkage of alkali-activated slag (AAS). It is found that the autogenous shrinkage of AAS paste can be reduced by 40% and 50% when replacing 10% and 20% slag with MK, respectively. By providing additional Si and Al, and decreasing the pH of the pore...journal article 2019
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Li, Z. (author), Zhang, Shizhe (author), Zuo, Y. (author), Chen, Wei (author), Ye, G. (author)Chemical deformation (chemical shrinkage/expansion), the absolute volume change during reactions, is a key parameter influencing the volume stability, especially the autogenous deformation of a binder material. This work, for the first time, reports an in-depth investigation on the chemical deformation of metakaolin based geopolymer (MKG)....journal article 2019
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Li, Z. (author), Liu, Jiahua (author), Ye, G. (author)This study investigates the drying shrinkage and the shrinkage-induced stress of alkali-activated blast furnace slag and fly ash concrete (AC) in comparison with ordinary Portland cement concrete (OC). For samples that were dried from 1 day after casting, the drying shrinkage of AC was much higher than that of OC. For samples that were stored...journal article 2019
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Bodnar, Taras (author), Dmytriv, Solomiia (author), Parolya, N. (author), Schmid, Wolfgang (author)In this paper, we construct two tests for the weights of the global minimum variance portfolio (GMVP) in a high-dimensional setting, namely, when the number of assets p depends on the sample size n such that p/n → c ϵ (0, 1) as n tends to infinity. In the case of a singular covariance matrix with rank equal to q we assume that q/n → c ϵ (0, 1...journal article 2019
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Oliveira, Bruna R F (author), Smit, Martijn P J (author), Veld, Harry (author), van Paassen, L.A. (author), Rijnaarts, Huub H M (author), Grotenhuis, Tim C. (author)Land subsidence in low-lying peatlands can be caused by shrinkage and organic matter oxidation. When these areas have networks of ditches and canals for drainage purposes, the sediments that accumulate in the waterways can be used to reverse the process of land subsidence. The objective of this study is to understand how dredged sediments can...journal article 2018
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Collier, Quinten (author), Veraart, Jelle (author), Jeurissen, Ben (author), Vanhevel, Floris (author), Pullens, Pim (author), Parizel, Paul M. (author), den Dekker, A.J. (author), Sijbers, JJM (author)Purpose: Diffusion kurtosis imaging (DKI) is an advanced magnetic resonance imaging modality that is known to be sensitive to changes in the underlying microstructure of the brain. Image voxels in diffusion weighted images, however, are typically relatively large making them susceptible to partial volume effects, especially when part of the...journal article 2018