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Jiang F.,University of Jinan | Jiang F.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials
Asian Journal of Chemistry

In this study, Al2(SO4)3·18H 2O and ZrOCl2·8H2O were used as raw materials to synthesize Al2O3-ZrO2 nano-powder with an average diameter of 70 nm was prepared by co-precipitation method in the ultrasound field. The synthetic process and properties of nano-powder Al 2O3-ZrO2 were studied by X-ray diffraction, differential thermal analysis, scanning electron microscopy and laser particle size analyzer. The results show that because of the activation ultrasonic radiation can not only make the precursor smaller and reduce it agglomeration but also slow down the speed of change to gel. Ultrasonic radiation can refine Al2O3-ZrO2 nano-powder effectively. The product was sphere-shaped particle with good dispersity. Source

Sun K.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials | Zhou X.,Brunel University | Gong C.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials | Ding Y.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials | Lu L.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials
Construction and Building Materials

An improved method for the densified mixture design algorithm and Fuller curve were used to design high-density sulphoaluminate cement concrete (HDSC). The performance of HDSC is significantly influenced by the paste thickness on the coated aggregates. Sulphoaluminate cement concrete mixtures containing aggregates coated with 3 different paste thickness of t = 10 μm, 20 μm, and 30 μm and water-binder ratios of 0.25, 0.30 and 0.35 were prepared. The results of experiments show that paste thickness on the coated aggregates significantly influences the mechanical properties and durability of HDSC. With the increase of paste thickness, the compressive strength is increased, but the electrical resistivity is decreased, particularly at the early ages of 1 and 3 days. The sulfate corrosion resistance coefficients of HDSC are larger than 1.0, the total porosity can be less than 7%, and the micropore (i.e. with pore size less than 20 nm) can be larger than 70%. © 2016, Elsevier Ltd. All rights reserved. Source

Cheng X.,University of Jinan | Cheng X.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society

Barium (strontium) calcium sulphoaluminate is a novel and derivative mineral compound of calcium sulphoaluminate by the partial substitution of barium or strontium for calcium, possessing the distinct properties of low calcination temperature, fast setting, high early strength, slight expansion as well as good corrosion resistance. This paper was to represent these types of cement. The crystal features, calcinations process as well as hydration theory of barium (strontium) calcium sulphoaluminate were investigated. The performances like the mechanical properties, corrosion resistance as well as permeability were obtained for barium (strontium) calcium sulphoaluminate cement. Moreover, alite-barium (strontium) calcium sulphoaluminate cement and belite-barium (strontium) calcium sulphoaluminate cement were fabricated via mineral combination techniques as the developed cements with the superior performance. Moreover, the practical application of these cement in-site was described, indicating a great potential for use in harsh environments. © 2015, Chinese Ceramic Society. All right reserved. Source

Li Y.,University of Jinan | Li Q.,University of Jinan | Li Q.,ShanDong Provincial Key Laboratory of Preparation and Measurement of Building Materials | Wang Z.,University of Jinan
Ceramics International

Laminated ZrC-SiC composites with different SiC powders were prepared through tape casting and hot pressing. Two different SiC powders, with sizes of 10μm and 800nm, were introduced into the laminated ZrC-SiC composite. The results show that there are obvious crack deflection and prolonged crack length in the laminated structure. Moreover, the composite B with a mean SiC particle size of 800nm is more compact than composite A (with mean SiC particle size of 10μm). The Si elements in composite A and composite B are pressed into the ZrC layer; fewer Zr elements spread to the SiC layer. The diffusion of Si elements of the SiC(2) (SiC particle size of 800nm) layer is easier and more uniform. Moreover, composite B has a higher density, lower porosity, and higher flexural strength than composite A. © 2015 Elsevier Ltd and Techna Group S.r.l. Source

Wang D.,University of Jinan | Yang P.,University of Jinan | Hou P.,University of Jinan | Zhang L.,University of Jinan | And 2 more authors.
Cement and Concrete Research

SiO2 oligomers, a kind of intermedium between silane and SiO2 nanoparticles, reveal small size, hydrophilic property, and high affinity with cement paste. In cement-based materials, the SiO2 oligomers transform into SiO2 nanomaterials. This is first time to report SiO2 oligomers created by the hydrolysis and condensation reactions of tetraethyl orthosilicate in an acetic acid solution to reduce the water absorption rate and modify the surface microstructure of cement-based materials. Mild acetic acid makes the stable formation of SiO2 oligomers which promote the reaction with cement phases. Linear, branched and 3D-chain structures of SiO2 particles can be formed in sequence during the condensation of oligomers. The water absorption rate of cement mortars treated with SiO2 oligomers was reduced to 46.4%. The SiO2 oligomers were ideal candidate as a surface-treated agent which resulted in surface densification of cement-based materials. © 2015 Elsevier Ltd. Source

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