Research On Preparation Of Foam Concrete Setting Time And Hardened Properties Control

As the foam concrete is light and porous, it not only can be used as wall materials, such as external insulation, concrete block, wall board, sandwich component, etc, but also can be applied in the engineering of backfill foundation, retaining wall etc. In this paper, we study the setting time and hardening performance of foam concrete slurry which is generated by mixed the ordinary portland cement and tea saponin foaming agent with accelerator. By studying the influence of the foam dosage, water-binder ratio, accelerator dosage on the setting time and various performances of foam concrete, we analyze the incidence of the various factors on the setting time and other performances and find out the optimal doping amount of each component. Finally, after mixed the mineral admixture with slurry, we research the influence of mineral admixture on the setting time and hardening performance.Research shows, under the circumstances that the foaming agent content is 0.03% and the accelerator is in the range of 2%~4%, the setting and hardening time will be shorten by 10%~15%, and the dry apparent density will be increased by 10%~15%, and the strength and water absorption will be increased by about 10% when the accelerator content increase 1% every time. Under the circumstances that the water-cement radio is in the range of 0.6~0.7, the setting and hardening time will be prolonged by 20%, and the dry apparent density will be decreased at a speed of about 5% when the water-cement radio increase 0.05 every time. When the foaming agent content is 0.03%, and the water-cement ratio is 0.5 which is not mixed accelerator, the dry density is 725 kg/m3, and the setting and hardening time is 750 min; however, the dry density is 634 kg/m3, and the setting and hardening time is 660 min when mixed with 2% of the accelerating agents and water cement ratio increases to 0.6. It can be seen that mixed with accelerator can shorten the setting time and reduce the effect of dry apparent density. Under the same water-cement ratio, it is hardly no difference for foam concrete on the dry density between the incorporation of minerals and undoped mineral admixture. However, due to the activity of cement is higher than the activity of mineral admixtures, the hardening time will be extended by 20% when mixed with mineral powder, and the hardening time will be prolonged by 30% when mixed with fly ash. Thought the strength of the foam concrete is decreased and the water absorption is increased after mixed with accelerator and mineral admixtures, they reach the JG/T 266-2011 standard requirement.This study has significance for the application of foam concrete.