A Study of Mix Proportions on the Properties of Alkali-Activated Slag Paste and Concrete by Silicate-Based Activator

• Main Authors: Chi-Che Hung, 洪啟哲
• Other Authors: Jiang Jhy Chang
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/50326974409091605440

博士 === 國立臺灣海洋大學 === 河海工程學系 === 99 === In this study, the influence of mix proportions for raw materials on the properties of alkali-activated slag paste and concrete by silicate-based activator are presented. Regarding alkali-activated slag paste (AASP), we investigated the influence of the various SiO2&Na2O dosage on the setting time and compressive strength of AASP, and examined the effects of the various curing environments on the compressive strength of AASP. Regarding alkali-activated slag concrete (AASC), we investigated the influence of three parameters including Sand/Aggregate ratio, Liquid/Binder ratio and Paste/Aggregate ratio on the fresh concrete properties, mechanical properties and durability of AASC. Results showed that the alkali modulus (weight ratio of SiO2 over Na2O) is the key factor influencing pH value. The higher alkali modulus results in higher strength for AASP, but the SiO2+Na2O dosage is the main factor influencing the strength and the setting time. The saturated lime water is a suitable curing environment to not only the ordinary Portland cement paste (OPCP) but also the AASP. In addition, for the AASC, the influence of the Liquid/Binder ratio on the 28-day compressive strength is not as apparent as the water/cement ratio is for the ordinary Portland cement concrete (OPCC). The AASC has superior strength and durability, and the 28-day compressive strength can reach 80% of the 91-day compressive strength. The trends of influences on the concrete properties for these three mixture variables are similar to those for the OPCC. It means that the experiences for making the OPCC should be able to be used for the AASC. This paper also provides lots of data for the AASC for future development of the mix design.