Construction Preparation

Pre-construction Equipment Preparation

Before construction, all necessary equipment and tools must be fully prepared. The main mechanical equipment required includes: a hot asphalt spraying truck with a heating device, professionally processed nozzles to ensure a misty spray and manual control over the amount; geotextile laying equipment to flatten and spread polyester geotextile, which can be either automatic or manually operated, but the laying must ensure the geotextile is straight and wrinkle-free; construction tools such as blowers, iron rollers, brushes, and transparent goggles, used for removing loose soil and debris, and for compacting the geotextile to adhere to the hot asphalt.

Inspect, debug, and perform routine maintenance on major machinery to ensure their integrity, and check and warranty the instruments.

2. Material Preparation

Key Construction Materials: Polyester Geotextile, Heavy Grade Petroleum Hot Asphalt

Material inspection prior to construction: After inspection, all materials meet technical specifications. An adequate quantity of tested and qualified polyester geotextile will be transported to the site, with a preparation of not less than 200m of geotextile laying. Half an hour before construction, heated bitumen will be applied or used from the asphalt storage tank, with the liquid heavy-grade asphalt being placed in the asphalt sprayer vehicle and transported to the site.

3. Field Inspection and Acceptance

Prior to laying the polyester geotextile, detailed identification and statistics are conducted on the field joints of new and old pavement subgrades. Horizontal cracks are marked, and all specifications of the slurry seal layer are checked for compliance. Afterward, the road surface is swept clean and blown off using cleaning tools. Stones or other debris left at the joints are cleared, and holes deeper than 2cm are filled with emulsified asphalt or asphalt mixture.

Polyester Geotextile Construction Techniques and Methods

The polyester geotextile construction process includes: surface cleaning and treatment of joint seams (transverse cracks) - layout marking - spraying hot asphalt adhesive - laying polyester geotextile - leveling and rolling - traffic control

Joint seam (crack) cleaning and repair

Prior to construction, thoroughly clean the joints between new and old pavement sublayers, as well as the dust, loose particles, and debris from the transverse cracks of the old pavement. For severely contaminated areas, perform a wash and apply emulsified asphalt as needed.

(2) Flatten out any sharp or uneven spots on the road surface. For severely damaged, sunken, or cracked areas, remove the cracked sections and fill and level them with asphalt material.

(3) For cracks between new and old road surfaces wider than 6mm, emulsified asphalt is used for filling; for cracks deeper than 2cm, asphalt material is employed for repair.

Before applying the adhesive oil spray, the working surface should have an adequate length, excluding the scattered sections at the bridgehead, with the general construction sections maintaining a length of no less than 200 meters.

(5) Keep the work surface dry and free of moisture; construction is only permitted after the road surface has dried following rain.

2. Pattern marking

After the supervising engineer's approval of the slurry seal, a baseline was set on both sides of the joints and cracks according to the width of the planned polyester geotextile. Using lime and chalk, lines were drawn 5 to 10 cm on either side of the centerline of the joints and cracks, serving as the positioning lines for laying the polyester geotextile.

3. Sprayed hot asphalt adhesive oil

The screed is in place. After positioning the equipment, adjust the geotextile on the support frame so that it is perpendicular to the joint seam, maintaining a taut overall flat state of the geotextile.

(2) Apply hot asphalt adhesive emulsion using an asphalt spraying truck within the range of new and old road marking. The width of the spray area for the adhesive emulsion should be 5 to 10 cm wider than the geotextile.

When applying hot asphalt adhesive, the construction temperature should be above 5°C, with the optimal hot asphalt temperature maintained between 160-180°C.

(4) When applying the hot asphalt adhesive, ensure even spraying and precise measurement. The recommended dosage is 0.8 to 1.0 kg/m2. Increase the asphalt amount moderately if necessary to achieve optimal bonding. Over-spraying can lead to wheel adhesion during high-temperature operations.

When applying hot asphalt, ensure necessary protection is in place beyond the two alignment lines to prevent road contamination.

(6) No hot asphalt emulsion should be applied during or immediately after rain when the road surface is wet. Spraying of asphalt emulsion should be scheduled only after the road has dried.

4. Installation and Seam Welding of Polyester Geotextile

Once the hot asphalt adhesive layer oil is sprayed and remains in a liquid state, immediately proceed with the installation of polyester geotextile using a polyester geotextile laying vehicle. Ensure that the distance between the asphalt spraying vehicle and the polyester geotextile laying vehicle is not too far, and the laying should closely follow the spraying, with the process being tightly coordinated.

When laying polyester geotextile using a tractor or a frame mounted on a truck, maintain a steady and even speed; do not accelerate or decelerate abruptly, and adjust promptly by hand to achieve a smooth laying effect.

(3) Equipped with paving equipment for brushing and iron roller to ensure the timely compaction of polyester geotextile onto the asphalt adhesive layer during installation. In case of wrinkling or creasing during installation, promptly use a cutting tool to sever the creased area, then rejoin it in the laying direction, bond and compact with adhesive layer oil, to ensure a good bond between the polyester geotextile and the adhesive layer oil.

During the installation of polyester geotextile, it should be laid as straight as possible. When a turn is necessary, cut the bend in the polyester geotextile, overlap the sections, and apply adhesive oil to bond them together, while avoiding wrinkles and creases as much as possible. If it is inconvenient to install in curves, minimize the length of the polyester geotextile laid.

(5) The longitudinal joint overlap width of polyester geotextile should be 5-10 cm, and the transverse joint width should be 10-15 cm. The transverse joint overlap direction should be in the direction of laying asphalt concrete, with the latter end pressed under the former end. The joints should be bonded securely with hot asphalt. The overlap width should not be too wide to prevent the interlayer from thickening at the overlap, which weakens the bonding strength between the surface layer and the base layer, leading to issues like surface layer bulging, detaching, or displacement. Therefore, any excessively wide overlap parts should be trimmed off.

(6) During polyester geotextile construction, field operators should wear protective gloves and eye shields to prevent burns from hot asphalt at high temperatures or finger injuries from the polyester geotextile.

(7) Do not use moisture-absorbed polyester geotextile during storage in the construction process.

(8) Sprinkle stone chips over the exposed hot asphalt on both sides of the laid geotextile to prevent the thin asphalt overlay from being lifted.

5. Traffic Control

Upon completion of the polyester geotextile laying construction, it should be avoided to allow pedestrians or vehicles to enter until the hot asphalt adhesive layer oil has cooled to room temperature. If immediate traffic opening is required, sprinkle an appropriate amount of fine sand or gravel promptly to prevent the polyester geotextile from being lifted or damaged by the vehicle tires sticking to the oil.

(2) No vehicles are permitted to suddenly brake or make sharp turns on the polyester geotextile to prevent significant damage.