The 2 nd International Malaysia-Ireland Joint Symposium on Engineering, Science and Business 2012 (IMiEJS2012) 235 The Effect of Damp Sand Content on the Geopolymerization Reaction of Fly Ash-Based Geopolymer Mortars Omar A. Abdulkareem 1a , A.M. Mustafa Al Bakri 1b , H. Kamarudin 1c , and I. Khairul Nizar 2d 1 Center of Excellence Geopolymer System Research, School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), P.O. Box 77, D/A Pejabat Pos Besar, Kangar, Perlis, 01000, Malaysia. 2 School of Environmental Engineering, Universiti Malaysia Perlis (UniMAP), Box 77, D/A Pejabat Pos Besar, Kangar, Perlis, 01000, Malaysia. a eng.omar83@yahoo.com*,mustafa_albakri@unimap.edu.my, c vc@unimap.edu.my, d nizar@unimap.edu.my. Keywords: damp sand, geopolymerization, alkaline activator, strength loss, fly ash. Abstract: The results of the current experimental investigation indicates the significant effect of the natural sand content prepared in damp condition on the compressive strength of fly ash-based geopolymer mortars prepared at different alkaline liquid content. The results show that applying Sand: FA ratios above 1.5:1.0 extremely deteriorate the geopolymerization process producing a geopolymer mortar without any reported strength. The lowest damp sand content at mass ratio of Sand: FA= 0.5:1.0, possess the minimum strength loss percent of 41, 55 and 37 % with respect to each Activator/FA ratios 0.3, 0.35, and 0.4. The trend of strength loss with increasing the damp sand content was strongly correlated with the nature of the geopolymerization complicated reaction and its dependency on the water content. The reported strength continued to decrease with increasing the water content which resulting from increasing the damp sand content. INTRODUCTION The ordinary Portland cement (OPC) production technology is the essential responsible for carbon dioxide (CO 2 ) emission to the atmosphere. It is estimated that the OPC production is contributing by about 7% of the greenhouse gases (GHS) emitted to the ambience [1]. Therefore, globally efforts are in progress to reduce the usage of OPC as a contraction material for environmental and technical basis. One of these efforts, the adoption of geopolymerization technology as possible alternative construction material to OPC. The geopolymerization technology can reduce the CO 2 emission by 80-90 % as compared with OPC, extremely low costs advantages with excellent mechanical and chemical resistance properties [1-4]. The geopolymer synthesizing technology is based on the alkaline activation (a mixture of NaOH/or KOH solution with sodium/or potassium water glass) of source materials rich in silicon (Si) and aluminum (Al) in amorphous form like the fly ash [3]. The resulted geopolymer material used as a binder instead of the ordinary cement binder which could bind the aggregate (fine or/and coarse) producing geopolymer mortar or concrete with excellent mechanical, thermal, and chemical resistance properties. Most reported researches adopted the aggregate in oven dry (OD) or saturated surface dry (SSD) conditions [5]. However, in practice the aggregate used in air dry (AD) condition or damp condition, because it is difficult to maintain the OD or SSD conditions in the field [5]. The current research represents an experimental study on the effect of the fine aggregate (natural sand) prepared in a damp condition on the geopolymerization reaction of fly ash-based geopolymer system. The damp sand condition in this study was achieved by sprinkling a tap water in similar condition existence in the field of making normal concrete. The