The effect of Pozzolanic reaction under different curing temperatures in strength development of RPC Dong-geun Jeong 1, a , Han-seung Lee 2, b 1 Dept. of Sustainable Architectural Engineering, Hanyang University (HYU), Seoul, South Korea 2 Dept. of Sustainable Architectural Engineering, Hanyang University (HYU), Seoul, South Korea a [email protected], b [email protected] ABSTRACT Many efforts have been poured at developing high strength cement based materials. Specifically the Pozzolanic reaction can greatly give influence on the strength development of the Reactive Powder Concrete (RPC). Since it has relatively large amount of silica components, the Pozzolanic reaction is activated. As the result, the micro-structure of the concrete matrix becomes denser and, it shows ultra high strength development. This study were analysed in Pozzolanic reaction ratios at the different curing temperatures(20 ° C, 60 ° C, 90 ° C, 150 ° C, 200 ° C, 250 ° C, 450 ° C). In order to analyze the Pozzolanic reaction ratio, the amount of Ca(OH) 2 was determined using TG/DTA. Through these analyses, the relationship between strength development and micro structural improvement caused by Pozzolanic reaction were investigated. MIP test was also conducted to evaluate the effect of the amount of porosity. Also, although Silica Fume (SF) is the best to be used as an admixture causing high efficient Pozzolanic reaction because of its high purity of silica, its market availability has become difficult. So, as an alternative of SF, Fly Ash (FA) and Blast Furnace Slag (BFS) were replaced instead of SF. This study focused on the strength development of modified RPC with different admixtures rather than SF under the various curing conditions. KEYWORDS: Reactive Powder Concrete (RPC), Pozzolanic reaction, Silica Fume, Fly Ash, Blast Furnace Slag, TG/DTA, MIP 1. INTRODUCTION Ultra High Performance Concrete (RPC) is a new generation of cement-based material by enhancing micro-structure of cement matrix. Comparing with concrete made of Ordinary Portland Cement (OPC), the advancements of RPC are particle size homogeneity, the amount of porosity and microstructure. According to past researches, the compressive strength can be reached the range between 200-800MPa. In order to achieve extraordinary properties, some principles are used, which are the elimination of coarse aggregates, reducing water to cement ratio and using high amount of silica components. Silica fume appears to be the most performing siliceous product among the pozzolanic materials. Its behaviour is related to the high content (>90%) of amorphous silica in form of spherical grains in the range of 0.01-1 μm. However, silica fume is not available in large amounts and it is also the most expensive mineral addition (about 750~4000 ₩/kg in Korea). The dosage of SF in RPC is very high (over 200kg/m 3 ) and, it can cause the increase of cost. So, this research aims to investigate the possibility of Blast Furnace Slag (BFS) and Fly Ash (FA) as the alternatives of SF. The same amount of SF is replaced with BFS and FA, and then observed the strength development. Test results indicate that RPCs incorporating BFS or FA show satisfying strength development compared to the normal 251
The effect of Pozzolanic reaction under different curing temperatures in strength development of RPC
May 03, 2023
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Related Documents
