Biaxial PP Plastic Geogrid
PP Plastic Biaxial Geogrid is manufactured from polypropylene by extrusion, punching and heating. It has a very high tensile strength and can be used for soil stabilisation, sub-base reinforcement and slope protecting projects.
The tensile properties of pre-punched geogrids are affected by the process parameters of longitudinal stretching and transverse stretching. The results suggest that the heating temperature, tensile speed and insulation time have significant influence on the mechanical performance of the pre-punched geogrid.
Strength
Biaxial PP Plastic Geogrid has high tensile strength in both longitudinal and transverse directions, making it ideal for soil reinforcement and stabilization. Its unique interlocking system helps prevent the movement of aggregate, and its ribs can distribute loads evenly, reducing sub-base thickness and construction cost. This is especially useful for large-area permanent Bearing foundations.
Several factors influence the mechanical properties of biaxial PP geogrids, including the structure of the pre-punched hole and technical parameters of the stretching process. The diameter-to-distance ratio and the percentage difference of longitudinal and transverse spacing are two major factors that can affect the mechanical properties of the geogrid. Moreover, the change regulation of longitudinal ribs during transverse stretching can also significantly affect its basic longitudinal mechanical properties.
The PP geogrid production process includes mixing extrusion, plate punching, preheating, longitudinal and transverse stretching, secondary heat preservation, cooling and shaping, cutting and winding. The result is a durable polypropylene grid with square apertures, which are optimally suited for all types of project fill materials. It is available in two aperture size ranges for optimum matching with the project fill.
In addition to its strong tensile strength, PP biaxial plastic geogrid is resistant to abrasion and long-term chemical degradation. It is also capable of withstanding the temperature extremes, from minus 45° to 50°C. It can be used in different Biaxial PP Plastic Geogrid applications, such as strengthening soft ground of highways and railroads, slope protection projects, and airfields.
Durability
Biaxial PP Plastic Geogrid is manufactured through several processes such as extrusion, punching, heating, longitudinal and transverse stretching. Its high tensile strength makes it durable and easy to install. The material is also resistant to acid and alkali and has a long service life. It is a good option for improving the bearing capacity of foundation and preventing cracking and subsiding.
The junction point in a geogrid is a critical area that may amplify stress concentrations due to its large size compared to the ribs. This is especially true for uniaxially loaded gridded materials. However, research has shown that the extrusion process strengthens the junction points by ordering the polymer chains, thereby increasing the overall tensile strength of the geogrid.
Other factors that can affect the tensile performance of a geogrid include its filler, coating, and temperature. For example, a study found that fiberglass coatings significantly decrease the shear resistance of the underlying material. On the other hand, thermosetting epoxy resin coatings improve tensile strength and shear resistance.
It is important to note that the tensile strength of a geogrid can be reduced by long-term degradation, such as site damage or creep. Therefore, it is common to use a reduction factor for the ultimate tensile strength of a geogrid in design. In addition, long-term degradation can Green 3D Geomat be mitigated by using a corrosion-resistant coating and adding carbon black to the raw material.
Flexibility
The flexibility of Biaxial PP Plastic Geogrid allows it to be installed in complex geological conditions with ease. The material is also highly resistant to abrasion, chemical and biological degradation. It can be used in a variety of applications, including construction, highways and railways. Its flexibility helps to stabilize the soil, preventing differential settlement and increasing bearing capacity. It also improves rail safety by preventing derailments. It also prevents migration of fines from the subgrade and helps to keep the ballast stable.
The flexible design of PP geogrids can be adjusted according to the specific requirements of the application. This can be done by altering the dimensions of the ribs and adjusting the aperture size. The ribs can also be made thicker or thinner depending on the load and application. This can increase the tensile strength and stiffness of the ribs, thereby reducing the deformation of the junction point.
In addition, the geometry of the pre-punched hole and the technical parameters of the stretching process can also affect the mechanical properties of the PP geogrids. For example, the heating temperature, tensile speed, insulation time and tensile ratio will have an impact on the performance of the geogrids. To achieve better results, it is important to select suitable process parameters. This can be achieved by using a simulation program, such as Abaqus, to simulate the biaxial stretching of PP geogrids with different pre-punched holes and to obtain laws about the stretching shape and mechanical properties.
Ease of Installation
PP Biaxial geogrids have two orthogonal sets of polymeric tension-resistant components that are commonly referred to as ribs and junctions. The ribs have apertures and they overlap each other to create a strong interlocking action with the soil. This helps to prevent lateral movement of the roadbed and minimize migration of fines from the sub-grade. It also provides high tensile loads in the transverse direction. It is therefore suitable for use in highway, railway and slope construction projects to stabilize the base soil.
The tensile strength of a PP biaxial geogrid can be improved by increasing the diameter-to-distance ratio. However, this can affect the processing technology and life of the punching die. The diameter-to-distance ratio should be selected according to the cost estimation.
Before biaxial stretching, the ribs of the pre-punched grid sheet must be deformed to a certain degree. The resulting deformation is uniform and allows the ribs to achieve their mechanical properties. However, when the longitudinal spacing is smaller than the transverse one, the longitudinal ribs will lose their mechanical properties during the transverse stretching process.
Generally, the biaxial PP plastic geogrid is stretched longitudinally before being transversely stretched. The longitudinal stretching causes less stress concentration in the longitudinal ribs than the transverse one. This makes the longitudinal ribs of the biaxial PP plastic geogrid better than the transverse ones.