Characteristics of meta-kaolin geopolymer Bender-Element (BE) test

• Main Authors: Piriyakul, Keeratikan, Iamchaturapatr, Janjit
• Format: Conference Proceeding
• Language: English
• Subjects: Geopolymer past; Meta-kaolinite; Shear wave
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2018.04.068

Bender element (BE) test is a non-destructive test and is commonly used as an ultrasonic shear wave (S-wave) technique for determining the stiffness of materials. In this research, the ultrasonic shear wave was measured by using the piezoceramic BE in order to monitor the setting and the hardening process of meta-kaolin based geopolymer (MKG). The S-wave was generated and received by piezoelectric ceramic sensors which were placed at opposite ends of the test samples. The effects of the thermal treatment on kaolinite, the mixing proportions between solid and liquid activator and the influence of sodium hydroxide to sodium silicate ratio (NaOH/Na2SiO3) were investigated. Liquid activators were prepared by using chemical portions between 10 M NaOH and Na2SiO3 of 1:1, 1:1.2, 1:1.5, 1:2, 1.2:1, 1.5:1 and 2:1. Subsequently, meta-kaolin (MK) powders were mixed with liquid activators by using solid to liquid rations (S/L) of 0.8:1, 1:1, 1.2:1 and 1.5.1. The physical and mechanical properties included this setting time and the shear modulus of fresh and hardened MKG specimens were measured by BE test. Experimental results showed that the S-wave velocity was closely related to the setting time by measuring penetration resistance (ASTM C403), which indicated that the S-wave velocity can be used to monitor the setting of fresh geopolymer and the long term evaluation of hardened geopolymer.