摘要：The quality of the the existing concrete surface in its repairing and strengthening is the key factor affecting the together working performance. The effective method to solve this problem is to use permeable crystal waterproof material to strengthen the existing concrete surface. In view of the existing old concrete which lacks free Ca2+ in the interior, the method of compensating calcium ion strengthening is proposed based on the action mechanism of permeable crystalline waterproof material. On the basis of DPS, calcium ion compensating agent Ca (OH)2, Na2SiO3(sodium silicate) and Na2CO3(potassium carbonate) solutes are added to prepare composite reinforcement solution for impregnation strengthening of concrete. Scanning electron microscopy (SEM) was used to observe the microstructure of the concrete before and after strengthening. It showed that after the entry of silicate ions, C-S-H colloid was formed by reaction with Ca (OH)2, and C-S-H gel blocked some pores, which made the inner microstructure more compact. The results of compressive strength before and after concrete strengthening show that the strengthening effect of calcium ion compensation method for low-strength concrete is better than that of permeable crystallization material strengthening method. The strength of C5 and C15 grade concrete is increased by 36.1% and 6% respectively, and the surface strength of 13.7 MPa concrete is increased by 16.7%.
