Effect of the Addition of ZrSiO 4 on Alkali-Resistance and Liquidus Temperature of Basaltic Glass Napaporn Vaiborisut 1,a , Chanittha Chunwises 1,b , Dararat Boonbundit 1,c , Sirithan Jiemsirilers 1,2,d , Apirat Theerapapvisetpong 1,e* 1 Research Unit of Advanced Ceramics, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok, 10330 Thailand 2 Center of excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok, 10330 Thailand a vaiborisut_napa@hotmail.com, b chanittha.chun@gmail.com, c d.dararatb@gmail.com, d sirithan.j@chula.ac.th, e* apirat.t@chula.ac.th Keywords: Liquidus temperature, Basaltic glasses, Zirconium silicate Abstract. Basalt fiber has been used as a reinforced material in cement-based materials because it has higher mechanical strength and cheaper than common silicate based glass-fibers. However, silicate-based glass fibers have low alkali resistance especially in cement matrix composite. In this work, we studied the improvement of alkali resistance by addition of zirconium silicate (ZrSiO 4 ) in original basalt glass composition. The batch of basalt glass with additional ZrSiO 4 contents of 0.00, 2.50, 5.00, 7.50 and 10.00 wt% were melted at 1500 °C. The liquidus temperature (T L ) is important in for the fiber glass manufacturing. It need to formulate glass composition which requires a lower melting temperature and is crystallization resistant. T L as a function of composition is usually determined experimentally. In this study, glassy phase was determined by X-ray Diffraction (XRD). The glass transition temperature (T g ), the crystallization temperature (T c ) and T L were analyzed by Differential Thermal Analysis (DTA). The results found that the addition of ZrSiO 4 in a basalt glass batch increased T g while T c of each sample was closed to original basalt fiber. Moreover, the alkali resistance of these glasses increased with an increasing of ZrSiO 4 content. However, excessive ZrSiO 4 contents (7.50 and 10.00 wt%) resulted in crystallization of ZrO 2 which separated from glassy phase. Introduction Basalt rock is a volcanic rock which able to form fiber glass by its component. The chemical components which are the major component in basaltic glass and influent on its properties are silicon dioxide, aluminum oxide, calcium oxide, magnesium oxide and iron oxide. Its structure is closed to the general silicate glass and enable to be used in glass melting [1,2]. The basaltic glass is commonly melted at high temperature between 1500 and 1700 °C. Basaltic glass was used in many composite materials as a fiber reinforcement due to its important properties, such as good electrical insulators, high mechanical strength, chemical resistance, and high temperature stability. Basalt fiber has an excellent thermal property, modulus of elasticity and high strength compared to those of S-glass and E-glass. However, the silicate based glass fibers have low alkali resistance especially in cement matrix composite. Among these fiber glasses, basalt fiber is higher resistance to alkaline environment and better insulation property, which is why it is widely used as an insulation material in the construction industry [3,4]. The addition of zirconium oxide (ZrO 2 ) to glass composition is to improve the alkali resistance. Besides improving alkali resistance of glass, glass-transition temperature and high temperature stability of sodium borosilicate glass and basalt fiber also increased [5,6]. On the other hand, the addition of more than 12.00 wt% ZrO 2 to the glass batch reduces the alkali resistance [7-9] and tensile strength of the basalt fibers [10]. The liquidus temperature (T L ) [11-13]plays an important role in an industrial glass. T L is defined as the highest temperature at which crystals can exist in equilibrium within the melt. During Key Engineering Materials Submitted: 2017-09-15 ISSN: 1662-9795, Vol. 766, pp 145-150 Revised: 2017-11-16 doi:10.4028/www.scientific.net/KEM.766.145 Accepted: 2017-12-19 © 2018 Trans Tech Publications, Switzerland Online: 2018-04-13 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.scientific.net. (#108017602-26/04/18,04:15:45)