Assessing Performance of Alkali Activated Calcined Kaolin Clay Based Self-Compacting Geopolymer Concrete Using Nanoparticles and Micro Steel Fiber

The sustainable production of self-compacting geopolymer concrete (SCGPC) is eco-friendly and has less carbon footprint than normal concrete. On the other hand, nanoparticles have been added to SCGPC in previous studies to enhance its characteristics. However, limited studies have concentrated on using nano-alumina and nanocalcium carbonate in SCGPC. Hence, in the present study, self-compacting geopolymer concrete was developed from locally available calcined kaolin clay (CKC) using two types of nanoparticles: nano alumina (NA) and nano calcium carbonate (NC), in light of the evaluation of its fresh and hardening properties. All SCGPC mixes were formulated with the total binder amount was 484 kg/m3 and a constant ratio of alkaline liquid to binder (AL/B) of 0.50. These mixes were divided into two systems, namely binary and ternary mixture systems. 100% of CKC was used in the control mix, while a combination of (98%CKC+2%NA) and (98%CKC+2%NC) was used separately in the first system (binary) and the second system (96%CKC +2%NA+2%NC) were mixed (ternary). Microsteel fibers (SF) were added to all SCGPC mixtures (SCGPCs) with a constant content of 0.5% of the volume of concrete. To evaluate the fresh properties of these mixtures, several tests were conducted. The tests were slump flow, L-box test, and flow time via V-Funnel. Also, the mechanical performance of SCGPCs was evaluated in light of the compression and splitting tensile strength tests. The results of fresh properties indicated a reduction in workability for all binary and ternary mixes compared to the control mix. However, the workability test results of all SCGPCs were in the required range determined by EFNARC. Moreover, incorporating NC and NA in binary and ternary mixes improved mechanical properties for all ages. However, the compressive and splitting tensile strengths were considerably enhanced up to (15.8% and 14.66%) for NA and (14.3% and 12.83%) for NC in the binary mixes, respectively. Meanwhile, the improvement reached (28.34% and 25.92%) in the ternary mixture at the age of 28 days.