Engineering Properties and Durability of Self-Compacting Concrete with No-Cement Eco-Binder Made from Ternary Recycling Industrial By-Products

• Main Authors: Hoang-Anh - Nguyen, Nguyen Hoang Anh
• Other Authors: Ta-Peng Chang
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/96721648518009939496

博士 === 國立臺灣科技大學 === 營建工程系 === 105 === This study investigated the engineering properties and durability of the high-strength self-compacting concrete (SCC) manufactured by an innovative no-cement SFC binder, which was purely produced with a ternary mixture of three industrial by-products of ground granulated blast furnace slag (S), low calcium Class F fly ash (F) and circulating fluidized bed combustion (CFBC) fly ash (C). To explore the possibility of applying this SFC-SCC to structural concrete, the bonding behaviors of the embedded steel bar confined by the SFC-SCC using the pull-out test was also conducted. With a fixed amount of circulating fluidized bed combustion fly ash at 15 wt.% of mixture of slag and Class F fly ash as the optimum value to activate the hydration, Class F fly ash in a wide range of 0-50 wt.% was used to adjust the properties of the SFC-SCCs at both fresh and hardened states. Experimental results showed that the compressive strengths of the resulting SFC-SCC at age of 28 days reached the value up to 65.6 MPa. The added amount of Class F fly ash up to 30 wt.% was found to be an optimal amount to produce the SCC with excellent flowing and passing capability, preferable durability and mechanical and bonding properties. Both mechanical properties and bonding strength of the no-cement SFC-SCCs were found to be lower than those of the plain ordinary Portland cement (OPC) concretes with similar water to binder ratio (W/B). On the other hand, at the equivalent 28-day compressive strength, similar bonding strength of SFC-SCCs to that of the plain OPC concretes was observed, but the required covering thickness of SFC-SCCs was lower than that of OPC concretes. The analysis on relationship between bonding and compressive strengths showed that the bonding quality of the SFC-SCCs was as good as that of plain OPC concretes implying that the former also could has a high potential of application as an alternative reinforced concrete for practical infrastructural construction. The results of microstructural analysis of the hydration products of SFC binder using Fourier Transform Infrared (FTIR) spectroscopy obviously showed that they mainly consisted of portlandite (Ca(OH)2) and anhydrite (CaSO4) which attributed to the hydraulic property of SFC powder. The main hydration products of the hardened paste are ettringite (AFt) and calcium aluminum silicate hydrate (C–A–S–H) gel. An increase in Type F fly ash addition led to the higher degree of AFt precipitation induced by an increase of active alumina.