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Gan, Y. (author), Yang, Shen (author), He, S. (author), Šavija, B. (author)Engineered cementitious composite (ECC) is widely employed in engineering due to its high toughness and ductility. The Interfacial Transition Zone (ITZ) between the fibers and the matrix plays a vital role in influencing the strength and durability of ECC. This study introduces a numerical method to simulate fiber pull-out behaviors,...journal article 2024
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Gan, Y. (author), Mirzaei, B. (author), Silva, J. R.G. (author), Cherednichenko, S. (author), Van Der Tak, F. (author), Gao, J.R. (author)We have studied THz heterodyne detection in sub-micrometer MgB2 hot electron bolometer (HEB) mixers based on superconducting MgB2 films of ∼ 5 nm (HEB-A), corresponding to a critical temperature (Tc) of 33.9 K, and ∼ 7 nm (HEB-B), corresponding to a T c of 38.4 K. We have measured a double sideband (DSB) receiver noise temperature of 2590 K...journal article 2023
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Gan, Y. (author)Ageing is an inherent feature of cementitious materials. Ageing of material leads to gradual loss of the function of a concrete structure with increasing likelihood of failure. As one of the typical ageing phenomena, fatigue of concrete, has recently received considerable research attention. The phenomenon of concrete fatigue is complicated as...doctoral thesis 2022
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Zhang, Y. (author), Liang, M. (author), Gan, Y. (author), Copuroglu, Oguzhan (author)Slag rim mainly consists of secondary precipitations such as C–S–H gel phase and hydrotalcite-like phase, which originate from the hydration of slag. In this paper, the micro-mechanical properties of slag rim were characterized by nanoindentation in combination with SEM. It was found that, compared to the C–S–H gel phase, slag rim showed about a...journal article 2022
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Liang, M. (author), Chang, Z. (author), He, S. (author), Chen, Y. (author), Gan, Y. (author), Schlangen, E. (author), Šavija, B. (author)Early-age stress (EAS) is an important index for evaluating the early-age cracking risk of concrete. This paper encompasses a thermo-chemo-mechanical (TCM) model and active ensemble learning (AEL) for predicting the EAS evolution. The TCM model provides the data for the AEL model. First, based on Fourier's law, Arrhenius’ equation, and rate...journal article 2022
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Gan, Y. (author), Zhang, Hongzhi (author), Liang, M. (author), Zhang, Y. (author), Schlangen, E. (author), van Breugel, K. (author), Šavija, B. (author)In this study, the flexural strength and fatigue properties of interfacial transition zone (ITZ) were experimentally investigated at the micrometre length scale. The hardened cement paste cantilevers (150 × 150 × 750 μm<sup>3</sup>) attached to a quartzite aggregate surface were prepared and tested under the monotonic and cyclic load using a...journal article 2022
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Zhang, Y. (author), Liang, M. (author), Gan, Y. (author), Copuroglu, Oguzhan (author)This paper reports the carbonation characteristics of a cement-slag system exposed to accelerated carbonation testing, and its improved carbonation resistance with the increasing MgO content in blast furnace slag, in which hydrotalcite-like phase plays a key role. Our research showed that the hydrotalcite-like phase started to carbonate upon...journal article 2022
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Mirzaei, B. (author), Gan, Y. (author), Silva, J. (author), Gao, J.R. (author)We will report a full demonstration of the Fourier phase grating used as 4.7 THz local oscillator (LO) multiplexer for Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO). The design, modeling, tolerance analysis, and experimental characterization of the angular and intensity distributions among 2 × 4 output beams and the...conference paper 2022
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Gan, Y. (author), Mirzaei, B. (author), Silva, J. R.G. (author), Laauwen, W. (author), Van Der Tak, F. F.S. (author), Gao, J.R. (author)We present an analysis of the bandwidth of an asymmetric 8-beam Fourier grating as the beam multiplexer for a 4.7 THz local oscillator used in a heterodyne receiver. We take the grating designed for NASA GUSTO balloon observatory as an example to address the bandwidth question although it does not need to operate over a wide frequency range....journal article 2022
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Liang, M. (author), Chang, Z. (author), Wan, Z. (author), Gan, Y. (author), Schlangen, E. (author), Šavija, B. (author)This study aims to provide an efficient and accurate machine learning (ML) approach for predicting the creep behavior of concrete. Three ensemble machine learning (EML) models are selected in this study: Random Forest (RF), Extreme Gradient Boosting Machine (XGBoost) and Light Gradient Boosting Machine (LGBM). Firstly, the creep data in...journal article 2022
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Chen, Y. (author), He, S. (author), Gan, Y. (author), Copuroglu, Oguzhan (author), Veer, F.A. (author), Schlangen, E. (author)This paper aims to provide a systematical review of the available printing strategies, sustainable cementitious materials and characterization methods for extrusion-based 3D concrete printing (3DCP). The printing strategies, consisting of printing setup, process, and material requirements, were summarized initially. In the material aspect,...journal article 2022
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Liang, M. (author), Gan, Y. (author), Chang, Z. (author), Wan, Z. (author), Schlangen, E. (author), Šavija, B. (author)This study aims to provide an efficient alternative for predicting creep modulus of cement paste based on Deep Convolutional Neural Network (DCNN). First, a microscale lattice model for short-term creep is adopted to build a database that contains 18,920 samples. Then, 3 DCNNs with different consecutive convolutional layers are built to learn...journal article 2022
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Xu, Y. (author), Gan, Y. (author), Chang, Z. (author), Wan, Z. (author), Schlangen, E. (author), Šavija, B. (author)Tailoring lattice structures is a commonly used method to develop lattice materials with desired mechanical properties. However, for cementitious lattice materials, besides the macroscopic lattice structure, the multi-phase microstructure of cement paste may have substantial impact on the mechanical responses. Therefore, this work proposes a...journal article 2022
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Liang, M. (author), Li, Z. (author), He, S. (author), Chang, Z. (author), Gan, Y. (author), Schlangen, E. (author), Šavija, B. (author)Stress evolution of restrained concrete is a significant direct index in early-age cracking (EAC) analysis of concrete. This study presents experiments and numerical modelling of the early-age stress evolution of Ground granulated blast furnace slag (GGBFS) concrete, considering the development of autogenous deformation and creep. Temperature...journal article 2022
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Gao, J.R. (author), Gan, Y. (author), Mirzaei, B. (author), Silva, J. R.G. (author), Cherednichenko, S. (author)Heterodyne receivers combining a NbN HEB mixer with a local oscillator (LO) are the work horse for high resolution (≥106) spectroscopic observations at supra-terahertz frequencies. We report an MgB2 HEB mixer working at 5.3 THz with<br/>20 K operation temperature based on a previously published paper [Y. Gan et al, Appl. Phys. Lett., 119, 202601...conference paper 2022
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Gan, Y. (author), Vandamme, Matthieu (author), Chen, Y. (author), Schlangen, E. (author), van Breugel, K. (author), Šavija, B. (author)This paper presents an experimental investigation on the short-term creep recovery of cement paste at micrometre length scale. Micro-cantilever beams were fabricated and tested with 8 different loading series using the nanoindenter. It is found that cement pastes show high recovery ratios (>80%) even subjected to very high stress levels....journal article 2021
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Gan, Y. (author), Romero Rodriguez, C. (author), Schlangen, E. (author), van Breugel, K. (author), Šavija, B. (author)This study presents an experimental investigation of the rate-dependent mechanical properties of cement paste at the microscale. With the use of a nanoindenter, micro-cantilever beams with the size of 300 μm × 300 μm × 1650 μm were loaded at five different strain rates from around 10<sup>−6</sup>/s to 10<sup>−2</sup>/s until failure. It is...journal article 2021
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Gan, Y. (author), Zhang, Hongzhi (author), Zhang, Y. (author), Xu, Y. (author), Schlangen, E. (author), van Breugel, K. (author), Šavija, B. (author)This study presents an experimental investigation of fatigue properties of cement paste at the microscale. A strong size dependence is found for the flexural fatigue life of the cement paste specimen. Microscopic observations on the fractured surfaces suggest that there is a higher density of nano-scale cracks generated during the fatigue...journal article 2021
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Chang, Z. (author), Xu, Y. (author), Chen, Y. (author), Gan, Y. (author), Schlangen, E. (author), Šavija, B. (author)In this work, the lattice model is applied to study the printing process and quantify the buildability (i.e., the maximum height that can be printed) for 3D concrete printing (3DCP). The model simulates structural failure by incorporating an element birth technique, time-dependent stiffness and strength, printing velocity, non-uniform...journal article 2021
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Gan, Y. (author), Romero Rodriguez, C. (author), Zhang, Hongzhi (author), Schlangen, E. (author), van Breugel, K. (author), Šavija, B. (author)This paper presents a method to numerically investigate the microstructural effect on the creep behavior of cement paste at the microscale. The lattice fracture model is extended to consider local time-dependent deformations of calcium-silicate-hydrate phases in the cement paste by imposing local forces. The term “experimentally informed...journal article 2021
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