Experimental investigation into the compressive strength development of cemented paste backfill containing Nano-silica |
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| Affiliation: | 1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China;2. Key Laboratory of High-Efficient Mining and Safety of Metal, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China;3. School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China;1. College of Resources and Safety Engineering, China University of Mining and Technology, Beijing 100083, China;2. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221116, China;3. Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada |
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| Abstract: | This paper investigates the influence of Nano-silica (NS) addition on the consistency and compressive strength development of cemented paste backfill (CPB). Tetraethyl-Orthosilicate (TEOS) was used as the precursor of Nano-silica along with ether-based Polycarboxylate superplasticizer (PCS). Two binder types (Portland cement and Slag-cement) and different amounts of TEOS (0.7–14% by mass of binder) with and without PCS are examined for 3, 7, 14, and 28 days curing time. Uniaxial compression tests for unconfined compressive strength (UCS) determination, slump height measurement, changes in gravimetric water content, and differential thermogravimetric analysis (DTG) were used to assess the influence of NS and admixtures (TEOS-PCS) on CPB performance. The results of this experimental study indicate that the addition of approximately 5% TEOS along with 0.5% PCS (by mass of binder) provide the best compressive strengths that can also be anticipated through the higher amount of calcium silicate hydrate (C SH) on DTG curves. It is also noticeable that the positive influence of NS is more evident when the amount of binder was decreased. The addition of PCS to CPB containing NS improved both the consistency of the mixture and the compressive strength development of CPB. |
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| Keywords: | Nano-silica TetraEthyl-OrthoSilicate Cemented paste backfill Polycarboxylate superplasticizer Compressive strength Binding agent |
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