Characterization and optimization of fresh and hardened properties of ultra-high performance geopolymer concrete
Mohamed Abdellatief, Mohamed Mortagi, Mohamed Abd Elrahman, Ahmed M. Tahwia, Ayed Eid Alluqmani, Hani Alanazi
Abstract
Due to the deterioration and environmental issues of cement-based ultra-high performance concrete (UHPC), there is an increasing interest in utilizing geopolymer technology to develop UHPC. Therefore, this paper presents a statistically based model using response surface methods to investigate the application of this approach to the design and optimization of ultra-high performance geopolymer concrete (UHPGC) mixtures. Twenty mixtures were designed and generated experimentally using the central composite design (CCD) concept. Flowability, bulk density, compressive and flexural strengths, and microstructure were investigated for various UHPGC mixtures. The effects of silica fume, natural sand, and degree of curing during thermal treatment on the UHPGC properties were also studied. The models presented herein reveal that all the inputs and outputs are perfectly correlated. Slag and silica fume are the two key components of UHPGC that affect the mechanical and microstructure while executing a multi-objective optimization. The change in sand content has a little impact on the properties of UHPGC, whereas the heat-curing temperature has a considerable impact on the geopolymerization process. From the experimental results, a sustainable UHPGC was produced with a flowability of 215 mm, a bulk density of 2521 kg/m3, and a compressive strength of 152 MPa. This study has laid the groundwork for designing and producing UHPGC materials utilizing the response surface method.