Lightweight Heat Resistant Geopolymer-based Materials Synthesized from Red Mud and Rice Husk Ash Using Sodium Silicate Solution as Alkaline ActivatorNguyen Hoc Thang, Pham Trung Kien and Mohd Mustafa Al Bakri AbdullahMATEC Web Conf., 97 (2017) 01119DOI: https://doi.org/10.1051/matecconf/20179701119