Preparation and evaluation of perfusion effect of grouting material for high-strength preplaced aggregate concrete
Preplaced aggregate concrete is a new type of concrete formed by pre-paving coarse aggregate in the formwork,then injecting grouting material to fill the aggregate gap.As an important component of preplaced aggregate concrete,the performance of the grouting material and perfusion quality influence the entire performance of the preplaced aggregate concrete directly,but the existing grouting material is difficult to meet the perfusion requirements of the high-strength preplaced aggregate concrete due to the lack of fluidity or strength.The orthogonal test was designed to explore the influence law of water-cement ratio,cement-sand ratio and cementitious material system on the working performance and mechanical properties of the grouting material,the preparation method of high-strength and high-fluidity grouting material was proposed.And simulated filling test of preplaced aggregate concrete was carried out with gravity perfusion and pumping perfusion,the perfusion effect of grouting material was verified from the aspects of appearance quality of test specimens,filling density and compressive strength.The results show that the water-cement ratio is the main factor affecting the comprehensive performance of the grouting material,the cement-sand ratio has a great impact mainly on the fluidity of the grouting material,double adding fly ash and silica fume can synergistically improve the working and mechanical properties of the grouting material.The effect of pumping perfusion used in the high-strength preplaced aggregate concrete is better than that of gravity perfusion,which can achieve higher compactness under the same conditions,but gravity perfusion can also reach a good perfusion density when using net slurry or higher-fluidity mortar as grouting material.With water-cement ratio of 0.3,double adding 15％fly ash and 4％silica fume,the net slurry with 35s fluidity value was prepared,and its 2 8 d compressive strength value was 70.9 MPa,the 2 8 d compressive strength of the preplaced aggregate concrete with dense perfusion can reach 96.8 MPa.
万方数据
