The Study On Inorganic Anchoring Materials Consist Of Metakaolin-based Geopolymer Mortar

Anchorage technology is one of the most commonly used reinforcement technology, more and more attention will be paid to the materials of this technology, while buildings tending clearly into the phase of repairment and reinforcement. Nowadays the organic anchoring materials, which is mainly used, exposes its shortcomings in high-temperature resistant and poor durability etc.. With advantages in these aspects, inorganic anchoring materials with high bearing capacity is urgent to be developed to meet the requirements of engineering. In the study, the advantages of Geopolymer in strength, durability, fire-resistance etc. were grasped to develop a new type of inorganic anchoring materials, which cementitious system is made up with alkali-activated metakaolin. Experiments to test the anchorage capacity of this metakaolin-based geopolymer materials were also conducted. The main task and conclutions of this study can be shown as follows:1. Develop a new type of inorganic anchoring materials which can meet the requirements of anchoring engineering. Orthogonal test was first used to explore how the raw materials effects the strength of metakaolin-based geopolymer, and then to figure out significance of each factor, finally to chose a optimization mixture ratio of metakaolin-based geopolymer. It’s turned out that the fluidity of metakaolin-based geopolymer is180mm, consistency is7.24mm/s, and setting time is10hours. The flexure strength at Id,7d,28d is3.55MPa,14.83MPa,15.21MPa, while the compressive strength is16.78MPa,74.47MPa,76.18MPa.2. Explore the anchorage performance of this new type of inorganic anchoring materials under air and water circumstance at room temperature. Pullout experiment of post installed rebar concrete specimens were prepared to achieve the target. As the results shows, the ultimate pull load of anchoring concrete specimens was24%higher than the yield load of rebar under air circumstance. With the anchoring length of10d, planting rebar was already yield, and extra anchoring length resulted in the decrease of anchoring strength. Anchoring strength of the specimens under water circumstance was very similar to the specimens under air circumstance, correspondingly the reinforced bars were already yield at the point of ultimate load.3. Explore the anchorage performance of this new type of inorganic anchoring materials at high temperature. Reinforced rebar were planted in special steel sleeve to conduct the pullout experiment under the temperature of100℃、200℃and300℃. The results shows that, the tensile shear strength (anchoring strength) keep almost constant at25℃,100℃,200℃and300℃. The anchoring rigidity first increased then lightly decreased with temperature rising from25℃to300℃, while anchoring rigidity at high temperature was also higher than that at room temperature.