Polymer modified cement-based repair materials research
|School||Central South University|
|Keywords||Polymer modified cement-based repair materials Performance Mechanical Properties Drying shrinkage Curing system|
Cement concrete pavement because of its high strength, excellent durability, and become one of the two major types of highway pavement, cement concrete pavement damage is also growing due to the development of the national economy and the sharp increase of the traffic, especially the most common pavement cracks, concrete The cracks in the road not only affect the appearance of pavement engineering, but also seriously affecting road traffic safety and comfort; cement concrete pavement crack repair, has important significance. Combination of domestic and foreign research progress of concrete pavement crack repair material, this subject through the polymer emulsion modified cement matrix to patch the cracks in the road to recovery pavement. The main contents and conclusions of this paper are as follows: 1, first using orthogonal test 5min viscosity and 7d compressive strength for control indicators, four-level orthogonal table by three factors, the use of four polymer emulsion SBR, EAV, CB SD modified cement-based materials, the primaries modified emulsion. Carboxyl styrene-butadiene latex SBR modified cement-based materials, 5min minimum viscosity best highest 7d compressive strength, modification effect. By orthogonal experiment to determine the initial mixing ratio of repair materials, optimized on the basis of the properties of the mixture ratio. The results show that: the water-cement ratio of 0.42 to 0.45, and the polymer dosage is 5% to 20%, the the modified paste the viscosity with increasing polymer dosage first increases and then decreases gradually increased with time large. The incorporation of the polymer can effectively improve the cement slurry groutability, the modified paste setting time has stagnated. 2, on the basis of optimized patching material ratio, the system studied polymer dosage, water-cement ratio and other factors impact on performance. The study showed that: polymer modified cement mortar compressive strength decreases with increasing polymer emulsion dosage, flexural strength first increases and then decreases. The addition of the polymer can effectively improve the the cement mortar toughness, improve resistance to chloride ion permeability of cement mortar. 3, the incorporation of the polymer can reduce the drying shrinkage of cement mortar. Modified cement mortar with ordinary cement mortar drying shrinkage trend similar to pre-shrink, post steadily. Modified cement mortar shrinkage decreases and then increases with increasing polymer dosage, the polymer content is 10%, the minimum modified cement mortar shrinkage. Polymer modified cement grout and cement mortar bond strength than ordinary cement paste and cement mortar, and after the first increases along with the increase of polymer dosage is reduced. Water-cement ratio of 0.42, the polymer content is 10%, the the modified slurry 28d bond strength than 7d bond strength of a growth of 52%, up to 28% increase in the same the 28d bond strength than ordinary cement paste; For modified cement mortar, polymer dosage of 5% to 10%, 28d bond strength than 7d bond strength increased by 36% to 38%, indicating that the polymer emulsion can significantly increase the bonding properties of cement-based materials. 5, five different conservation methods on the strength of the polymer modified cement mortar, the results show that: the polymer modified mortar water conservation should not be too long. First water conservation 3d, and conservation in dry conditions most favorable to the strength development.