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Advances in Materials Science and Engineering
Volume 2016, Article ID 8792817, 13 pages
http://dx.doi.org/10.1155/2016/8792817
Research Article

Study on Microstructural Evolution and Strength Growth and Fracture Mechanism of Cemented Paste Backfill

1Key Laboratory of the Ministry of Education of China for High-Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China
2School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China

Received 14 June 2016; Revised 28 July 2016; Accepted 31 July 2016

Academic Editor: Charles C. Sorrell

Copyright © 2016 Jian-Xin Fu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The relations among the uniaxial compressive strength of cemented paste backfill (CPB) with solid phase mass fraction, cement sand ratio, and curing age were studied. The UCS of CPB samples increased exponentially with the increase of solid phase mass fraction and curing age but increased linearly with the increase of cement sand ratio. The results of X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that the strength was determined by the amount of ettringite and C-S-H gelling. With the increase of ettringite and C-S-H gelling, the strength became larger. The triaxial compression test was conducted by selecting four kinds of CPB samples. The results showed that, with the increase of confining pressure, peak and residual strength became larger, but the elastic modulus decreased. When the ratio of confining pressure and uniaxial strength is about 1 : 2, the CPB samples show significant ductility characteristics and the ratio of residual strength and peak strength increased obviously.