(1) direct grouting method: it is suitable for non-expansion and contraction cracks. ① Clean the joints; (2) Apply a layer of polyurethane primer to the joints and pavements, with a thickness of 0.3 0.1mm and a primer dosage of 0.15g/m2; (3) Prepare grouting materials, pour them into joints, and open them to traffic after curing.
⑵ Pressure grouting method: it is suitable for non-expansive surface cracks below 0.5mm (pressure grouting) or cracks around 3mm (injection grouting). ① Clean the joints; (2) filling materials with joints; ③ Grouting with compressed air nozzle or syringe; (4) Heating and curing before opening to traffic.
⑶ Grouting method: it is suitable for slight cracks less than 3 mm .. (1) Use percussion drill to enlarge the cracks along the cracks into grooves of1.5 ~ 2.0cm, with the maximum depth not exceeding 2/3 of the thickness; (2) Clean the joints and fill them with clean pebbles with a particle size of 0.3~0.6 cm (silt content less than 1%); (3) Joint filling with good grouting materials; (4) Heating and curing, and opening to traffic after reaching the strength.
⑷ Tape coating method: It is suitable for medium cracks with a thickness of 3 ~15 mm.. (1) Cut about 15cm along both sides of the crack, cut two transverse joints 7 ~ 10 cm deep in parallel cracks, and chisel out this part of concrete; (2) drill a pair of palladium nail holes at 10cm along both sides of the seam at intervals of 50cm, and drive a pair of palladium nail grooves with the same diameter as the palladium nails between the two palladium nail holes; (3) Using φ 16 steel bar as palladium nail, with a length of 20cm and a hook length of 7cm, filling holes and grooves with quick-hardening mortar, and installing palladium nail; (4) slotting and chiseling, and cleaning the surface; ⑤ Brush a layer of cement mortar with the same proportion on the repair surface, and then pour quick-hardening concrete; ⑥ Spraying health care agent for health care; ⑦ Use a cutting machine to cut seams and fill building materials.
5] Full-depth patch method: it is suitable for serious cracks with crack width greater than 15mm and staggered platform greater than12 mm. Concrete patch can restore the ability of cracks to transfer load between plates and minimize vertical deformation. It can be divided into aggregate locking method (suitable for joints with staggered contact surfaces of reinforced concrete pavement of secondary highway), planing control method (namely inverted T-shaped method, which can only provide load transfer on one side of each joint due to the lack of joint system with horizontal edges) and dowel bar method (suitable for pavement with cold climate and heavy traffic load). (1) Cut off the damaged surface, and the sawing distance shall be at least 30cm from the damaged position. Saw a 5cm deep seam along the inner side at the bottom edge of the reserved plate, and clean the cut concrete block; (2) Check whether the surface of cushion or base is wet and dense; (3) The concrete mixture ratio meets the design and specification requirements, and the water cement ratio is not greater than 0.4; (4) The concrete should be paved within 30 ~ 40 min, vibrated and compacted, and then cured with curing agent; ⑤ Within 12h after concrete paving, saw the contraction joint in the middle of the plate to the thickness of14, and fill the joint filler in the contraction joint, and seal the joint within 5d after concrete paving.
2. Local repair
(1) For slight cracks with slight peeling, cut them into rectangular grooves with a depth of about 5 ~ 7 cm, and fill them with quick-setting pebble concrete after scrubbing.
⑵ For the broken plate with slight crack, wide crack and slight peeling, open a groove with a depth of 20cm on both sides of the crack to half the thickness of the plate, drill holes on both sides of the crack in the direction parallel to the center line at the bottom of the groove with a spacing of 30 ~ 40 cm. After cleaning the groove and hole, install Grade II steel bars and fill them with high-grade mortar. Finally, the quick-setting concrete with the same label as the original pavement is poured until the pavement is smooth.
(3) Make a hole in the center of the thickness on both sides of the groove, with a depth of 10cm, a diameter of 4cm and a horizontal spacing of 30-40cm. Wet the hole, insert 18 ~ 20 mm, about 20cm long steel bar, and then fill it with quick-setting mortar and tamp it. After the mortar hardens, pour the quick-setting concrete and tamp it until the road surface is smooth.
3. Replace the whole board. Measures shall be taken to replace the broken plates with serious fracture, serious spalling at cracks, plates divided into more than three pieces, dislocations or cracks that have started to move. First, the subgrade and base are treated, and then the concrete slab is poured again with quick-setting materials, or replaced with concrete precast blocks and strips. For sections with poor subgrade stability and incomplete settlement, precast blocks should be used for replacement and filling, and cement stabilized cushion should be used for base course. The gap of the repair block should be filled with cement mortar or asphalt rubber to prevent water seepage damage.