Construction plan for fiberglass geogrid

Construction plan for fiberglass geogrid

To effectively prevent and control the diseases caused by reflective cracks in the pavement base layer, fiberglass grilles can play a reinforcing role.
Fiberglass geogrids are widely used in today's highway construction. There are two commonly used types of fiberglass geogrids: those with self-adhesive adhesive and those without self-adhesive adhesive. Those with self-adhesive adhesive can be directly laid on the already leveled base layer, while those without self-adhesive adhesive are usually fixed with nails.

 

Fiberglass Grille

Asphalt fiberglass grid

Bitumen Fiberglass Geogrid

Ⅰ Introduction and Performance of Fiberglass Grille

Fiberglass grating is a new type of road material, which is an excellent geotextile material for enhancing road base and roadbed. This product is made of glass fiber woven and coated, and when combined with the top layer asphalt mixture, it will improve the flexural tensile strength and deformation resistance of the asphalt mixture, significantly improve its fatigue resistance, reduce, delay or eliminate reflective cracks.

Fiberglass grating has high tensile strength in both longitudinal and transverse directions, low elongation, and high tensile modulus.

Performance parameters of fiberglass geogrid

Ⅱ Construction technology

2.1 Preparation of personnel, machinery, and materials before construction
Fiberglass cloth is laid manually and must be laid immediately after spraying the adhesive layer oil to prevent viscosity reduction caused by asphalt cooling and ensure the consistency of each process
Clean the road surface with polyester fiberglass cloth: remove dirt, gravel, and dust to ensure the bonding effect of asphalt
2.2 Fiberglass grating laying
Glass fiber geogrid without self-adhesive adhesive can be used to enhance asphalt concrete pavement and prevent reflection cracks between the pavement and the road surface. The anchoring method can be used for construction, but it is advisable to first lay the glass fiber geogrid and then sprinkle hot asphalt as the adhesive layer oil. Construction personnel must wear gloves, and the construction method is as follows:

1) The adhesive layer oil should be AH-70 or AH-90 heavy oil hot asphalt, and the specifications and quality of the adhesive layer oil should comply with the "Technical Specification for Highway Asphalt Pavement Construction" JTJ032-94, and special vehicles should be used for spraying alcohol. The amount of adhesive oil used per square meter is about 0.4kg-0. 6kg
2) When laying fiberglass geogrids, the laying should be smooth and tight, with a horizontal overlap length of 50-100mm and a vertical overlap length of 150-200mm. According to the paving direction, the rear end should be pressed under the front end.
3) Use a rubber tire roller to compact the road.
4) A fixed iron sheet of 50 x 50 x 0.3mm, which is required to be flat and not warped, with chamfered edges and 2-inch steel nails.
5) When using the nail fixation method to lay fiberglass geogrids, one end is first fixed with a fixed iron sheet and nails on the lower structure of the asphalt layer that has been sprayed. The nails can be hammered or shot in by a gun. Then, when the grid is longitudinally tightened, the fiberglass is in a straight and tensioned state horizontally.
6) When fixing the nails, the overlap distance of the grid is: the overlap distance of the longitudinal joint is not less than 15cm, and the overlap distance of the transverse joint is not less than 5cm. The longitudinal overlap should be placed on top of the previous one according to the direction of asphalt paving.
7) When fixing, the nails should not be nailed onto the fiberglass, nor should they be directly struck with a hammer. If the nails are found to be broken or the iron sheet is loose after fixing, they need to be re fixed
8) To prevent the tires of construction vehicles from sticking the fiberglass grille and adhesive oil together. The phenomenon of wheel slippage in the asphalt concrete paver should be caused by scattering stone chips on the surface of the adhesive layer oil, with a stone layer dosage of 3m3/1000m2-5m3/1000m2.
9) Construction shall not be carried out when the atmospheric temperature is below 10 degrees Celsius or the road surface is damp
10) The construction method of asphalt surface layer is the same as that of ordinary asphalt pavement surface layer, but it should be noted that construction vehicles should not make sharp turns or brake sharply on the surface of the fiberglass grating.

Ⅲ Construction precautions for fiberglass geogrids
Glass fiber geogrid has become irreplaceable information in the application of dealing with reflective cracks in asphalt pavement. It has high tensile strength and low elongation in both warp and weft directions, and has high temperature resistance, low cold resistance, aging resistance, inerting resistance and other functions. It is widely used in the reinforcement of asphalt pavement, cement pavement and subgrade, railway subgrade, embankment slope protection, airport runway, sand prevention and control and other projects. In the plan, fiberglass grilles will be placed between the lower and middle layers of asphalt concrete. The main feature of fiberglass grilles is their high tensile strength and elastic modulus, which have a similar effect to the steel bars in reinforced concrete. Fiberglass geogrid can withstand high temperature rutting: Asphalt concrete has rheological properties at high temperatures, specifically manifested in: the asphalt road surface layer becomes soft and sticky in summer; Under the action of vehicle load, the stress area produces a depression, and after the vehicle load is removed, the asphalt surface layer cannot fully recover to its pre load condition, resulting in plastic deformation; Under the repeated rolling of vehicles, plastic deformation accumulates continuously, forming ruts. After analyzing the structure of the asphalt surface layer, we can know that due to the rheological properties of asphalt concrete at high temperatures, there is no mechanism in the surface layer that can constrain the movement of aggregates in asphalt concrete under load, resulting in the displacement of the asphalt surface layer, which is the main reason for the formation of ruts. Fiberglass geogrids are used in the asphalt overlay, which serve as a skeleton in the asphalt overlay. The aggregates in asphalt concrete penetrate between the geogrids, forming a composite mechanical interlocking system that restricts the movement of the aggregates and increases the lateral constraint force in the asphalt overlay. The various parts of the asphalt overlay are restrained from each other, preventing the displacement of the asphalt overlay and thus resisting rutting
The application of fiberglass geogrid to resist low-temperature shrinkage cracking in asphalt overlay greatly improves the tensile strength of asphalt concrete, which can resist large tensile stresses without causing damage. In addition, even if cracks occur in local areas, the stress at the crack location is too concentrated, but gradually disappears through the transmission of fiberglass geogrid, and the cracks will no longer develop into cracks. When choosing fiberglass geogrid, In addition to meeting the performance indicators specified in the table above, special attention should also be paid to ensuring that its width is not less than 1. 5m to ensure sufficient cross-sectional area to fully dissipate crack energy when used as a control reflection crack interlayer; Meanwhile, the mesh size should be 0.5-1 of the larger particle size of the asphalt surface layer material on it. 0 times, this helps to achieve good shear adhesive adhesion, promote aggregate interlocking and restriction.