Mixed sand concrete grouting material preparation and the selection of sand ratio

grouting material secondary grouting equipment foundation grouting material made of high-strength aggregate rigid concrete grouting material can improve the compactness and deformation modulus, thus reducing the deformation under load. Due to uneven shrinkage deformation of cement produce internal stress, which result in the crack of the concrete grouting material. The shrinkage of concrete grouting material can restrict, reduce the shrinkage of concrete grouting material than cement for several times. In addition, the price is cheap, cement aggregate concrete grouting material economic and practical. In order to make the aggregate play a role of the above, the aggregate needs to have certain technical requirements, such as robustness, grading, apparent density, etc. Mechanism of sand properties affect the performance of concrete grouting material is mainly manifested in the following areas; 1, the mechanism of sand particles in the slurry can play a role skeleton, limit deformation of the cement and aggregate between sliding. 2, the mechanism of sand surface is rough, thus can increase the interface bonding strength of cement. 3, also contains some mechanism of sand stone powder, the powder can improve the hydration products of crystallization degree, the increase of crystal glue than reduce deformation of cement under the action of external force. Mechanism of 4, compared with natural sand, sand particle surface is rough, with pure mechanism sand mixing grouting material series grouting material with poor workability of concrete. The general mechanism of sand grain size distribution in 1. 18 mm above accounted for the total amount is about 50%, and the general river sand only accounts for about 20%; Particle size in 0 Shanghai sleeve grouting material. 3 mm the following content is only 15% or so, this part to improve the workability of concrete grouting materials have very important influence. River sand particle size in 0. High 3 mm below the content above 50%, the specific surface area is big, with their level of preparation with strength and slump of concrete grouting material, concrete grouting material of water consumption increases, the dosage of cement, plastic shrinkage increases, the possibility of early cracking, abrasion resistance, permeability resistance of concrete grouting, and lower than the coarse sand concrete grouting material and the mechanism of sand concrete grouting material. Sand grain size distribution, it indicates that the sand grain size of collocation. The gap between particles in the concrete grouting material is made up of the slurry filling, in order to reach the goal of saving cement and improving strength, should try to reduce the space between the particles. Mechanism sand and fine sand use collocation, overcome the mechanism sand when using fine particles less alone, especially fine coarse particle little faults, can effectively reduce the porosity and specific surface area, reducing fewer particles when used alone, especially fine coarse particle little faults, can effectively reduce the void fraction and total surface area, reducing the cement dosage of unit volume concrete grouting material, improve the workability of concrete grouting material mixing content and improve the compactness and strength of concrete grouting material.