Author
Rujia Qiao
Bio: Rujia Qiao is an academic researcher from Xi'an University of Architecture and Technology. The author has contributed to research in topics: Concrete recycling & Aggregate (composite). The author has an hindex of 4, co-authored 10 publications receiving 31 citations.
Papers
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TL;DR: A comprehensive review of the scientific and technical achievements of microwave-assisted concrete treatment can be found in this article, where the theoretical fundamentals for the microwave assisted concrete heating process are investigated in detail, covering areas such as the microwave heating characteristics, governing equations, dielectric properties and multi-field coupling effects.
35 citations
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TL;DR: In this article, a new model to predict the permanent strain of unbound gravel mixture was proposed based on the performance of single-size gravels and the contribution of coarse and fine aggregate in the gravel mixture.
16 citations
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TL;DR: In this paper, the authors investigated the heating process of aggregate-mortar interfaces under microwave irradiation and provided a contribution and reference for the further application of microwave-assisted aggregates recycling.
14 citations
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TL;DR: In this paper, the effect of compaction energy was considered in frozen stage under closed system, and the results showed that frost-heave ratio first increased with the increase in fine content, and then decreased with the increasing in fines content.
Abstract: Compactness is an important parameter to guarantee the subgrade stability, which is dramatically affected by temperature, especially in cold region. In this paper, the effect of compaction energy was considered in frozen stage under closed system. Frost-heave tests with different fines contents and moisture contents with non-water supply under different compaction energy conditions were carried out to find out the relationship between compaction energy and frost-heave ratio. Results showed that frost-heave ratio reached its maximum in the standard compaction energy test, minimum in the insufficient compaction energy test, and median in the over compaction energy tests. Surprisingly, frost-heave ratio first increased with the increase in fines content and then decreased with the increase in fines content. The water weight of absorption per unit area was also set up to explain it. It is an interesting discovery.
12 citations
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TL;DR: In this paper, the authors investigated the fracture behavior of commonly used coarse aggregates: granite and basalt were investigated by microwave heating tests and found that basalt fracture occurred with more damage at higher power level.
11 citations
Cited by
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TL;DR: In this paper , the micro-structural characteristics of the loess specimens that are exposed to acetic acid or sodium sulfate, are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy analyses.
Abstract: When exposed to chemicals, the micro-structural evolution of the loess and the impacts on the macro-mechanical properties are considered crucial for contaminated land reclamation. In this study, the micro-structural characteristics of the loess specimens that are exposed to acetic acid or sodium sulfate, are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy analyses. Further, their macro-mechanical properties are determined by direct shear tests. The corrosion of the cement between particles under acetic acid environments and the salt-induced swelling under saline conditions play an important role in the micro-structural deterioration. The cohesion and friction angle for the wetted loess are about 16 kPa and 19° respectively, while for the acetic acid-contamianted loess, they reduce to 10 kPa and 15° respectively. They, for the sodium sulfate-contaminated loess, reduce further to below 10 kPa and 13° respectively. The macro-mechanical properties show good correspondence with the micro-structural deterioration.
38 citations
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36 citations
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TL;DR: In this paper, the hydraulic conductivity in gravelly soils containing various contents of gravel particle fraction under cyclic freezing-thawing was investigated, and the results showed that hydraulic conductivities significantly depend on gravel content, confining stress, number of F-T cycles and initial water content.
30 citations
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TL;DR: In this article , the intrinsic effect of microwave pre-curing on the hydration kinetics and microstructure development of UHPFRCs is investigated. And the observed experimental results show that the microwave treatment can create a dense shell around the cured UHPC's periphery, which can resist the lateral deformation of the specimen and guarantee the excellent mechanical properties of the treated sample.
Abstract: This research aims to clarify the intrinsic effect of microwave pre-curing on the hydration kinetics and microstructure development of Ultra-High Performance Concrete (UHPC). Six hours after casting, the UHPC samples are subjected to microwave pre-curing for 60–240 s. Then, the macro and micro characteristics of the cured UHPC are evaluated. The observed experimental results show that the microwave treatment can create a dense shell around the cured UHPC's periphery, which can resist the lateral deformation of the specimen and guarantee the excellent mechanical properties of the treated sample. Moreover, when steel fibres are included into UHPC, the reflection and shielding effect of the 3D fibres network can significantly block the promotion effect of microwave on the strength development of UHPFRC. Additionally, due to the high energy of microwave, high polymerization hydration products and advanced pore structure (micro and meso scales) can be observed in the pre-cured UHPC.
25 citations
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TL;DR: In this paper , a comprehensive study of the different effects of different curing methods on the strength development of normal concrete and UHPC is presented. But, it is not practical to specify the peak curing regimes for concrete or UHC since the best results need critical monitoring of curing parameters.
25 citations