Airport Runway Full-Slab Rapid Replacement Cement Apron Quick-Drying Cement

With the development of the aviation industry, the total mass and tire pressure of civil aircraft are continuously increasing, thus imposing higher demands on airport pavements. Not only is sufficient load-bearing capacity required (i.e., meeting strength requirements), but the pavement must also possess good usability quality. This means that while the pavement should be smooth, it must also have a certain roughness to ensure stable and comfortable taxiing, easy braking, and to prevent hydroplaning on wet surfaces or during rainy conditions, thereby ensuring aircraft safety. I. Excavation and Replacement of Cement Concrete Slabs 1. For severely damaged sections of cement concrete slabs where the thickness is less than 15 cm, the damaged slabs should be excavated and replaced. Use C30 concrete to replace the excavated damaged slabs. The damaged sections of the base layer should be removed, and the roadbase should be reinforced with C15 concrete. The top surface elevation of the reinforced concrete should be level with the existing base layer. 2. ① When removing old slabs, care should be taken to minimize impact on adjacent slabs, and existing tie bars should be preserved as much as possible. Use hydraulic breakers to remove broken concrete, and promptly clear away concrete debris. ② Remove damaged sections of the base layer and compact the base. For individual slab bases, reinforce the roadbase with C15 concrete, ensuring the top surface elevation matches that of the existing base layer. Apply a 20 cm wide asphalt strip on the base layer at the joints of the concrete slabs. ③ Replace the excavated damaged slabs with C30 concrete. Use commercial concrete delivered to the site via specialized concrete transport vehicles. Compact with insert vibrators, level with a vibrating beam, and finish manually. Treat the concrete surface to match the existing pavement texture. If the original slab contained reinforcement mesh, the new slab should also include it, and tie bars to adjacent slabs should be restored. Use curing compounds for curing. Cut joints in adjacent slabs to a depth of 1/4 of the slab thickness using a joint cutter. Remove debris from the joints and fill with joint sealant. ④ Excavation and replacement refer to the damaged slabs on the old road that require removal. Specific repair locations are detailed in the "Yanhuang Road Pavement Excavation and Repair Quantity Table." II. Repair and Treatment of Original Cement Concrete Slabs 1. Joint Treatment ① For fine cracks less than 3 mm wide, use expansion grouting: first widen the crack into a 1.5–2.0 cm groove, with a maximum depth not exceeding 2/3 of the slab thickness. Remove concrete debris, fill with clean stone chips, then inject joint sealant. Open to traffic only after the material has cured and reached strength. ② For medium cracks between 3 mm and 15 mm wide, use strip overlay for repair. When cutting on both sides of the crack, ensure the cuts are parallel to the contraction joints and at least 15 cm from the crack. Remove concrete, install dowel bars, roughen the inner walls of the crack, remove debris and surface dust, and exposed aggregate. Finally, pour concrete. ③ For severe cracks wider than 15 mm, use full-depth repair (aggregate interlock method). Make parallel cuts, remove broken concrete, reinforce the base layer, then pour cement concrete. Open to traffic only after strength is achieved. 2. Edge and Corner Repair ① For broken corners, determine the cutting range based on the size of the fractured surface. The minimum longitudinal cutting width is 0.5 m, and the maximum is 1.0 m; the minimum transverse width is 0.5 m, extending to the center of the lane. Carefully cut the damaged slab to avoid additional damage to adjacent slabs. After cutting, remove the damaged section to form a regular vertical surface. Existing reinforcement should not be cut; if it is difficult to preserve all reinforcement, at least retain 20–30 cm of rebar ends, staggered in length. If the base layer is loose, excavate and replace with C15 concrete as the base. ② Slab repair: For spalling at the edges of cement concrete panels, clean the spalled surface and repair with asphalt mixture or joint material. ③ Corner repair: For broken corners, determine the cutting range based on the size of the fractured surface. Ensure vertical cuts, apply asphalt to the joint surface with the existing slab, and if it is an expansion joint, install a joint filler. Then pour cement concrete and open to traffic after strength is achieved. ④ Damaged joint sealant repair: Remove old sealant and debris before repairing the joint. ⑤ Longitudinal joint opening repair: When transverse displacement of adjacent lane panels causes longitudinal joint openings less than 10 mm, use heated-applied sealants such as PVC mastic, tar-based sealants, or rubber asphalt. For openings between 10–15 mm, use polyurethane cold-applied sealants. For openings larger than 15 mm, use asphalt sand for filling. ⑥ Longitudinal joint破碎 repair: Cut a planned shape around the破碎 area outer edge, with vertical cut surfaces and a flat base. Remove concrete debris before filling and repair. 3. Treatment of Faulting in Cement Concrete Slabs After grouting and crack treatment are completed, address slab faulting. For faulting ≤ 0.10 mm, use mechanical grinding or manual chiseling to level. For faulting > 0.10 mm, first level by chiseling, then overlay with a leveling course, or partially excavate and reconstruct (depending on site conditions). 4. Treatment of Potholes in Original Cement Concrete Slabs For individual potholes, remove debris and fill with materials like cement mortar to achieve a smooth and dense surface. For multiple connected potholes, use thin-layer repair: cut potholes to a depth of at least 6 cm, compact thoroughly, and ensure level with the original concrete panel. 5. Treatment of Joints in Original Cement Concrete Slabs Joints in concrete pavement include longitudinal construction joints, longitudinal contraction joints, transverse construction joints, and transverse expansion joints. Joints are most prone to damage, and many joints in this project area have damaged or unsealed filler. First, clean the joints with a blower or vacuum to remove dust, then fill with joint sealant. Use polyurethane sealant as the joint filler for injection.