FRP/GRP manhole cover

Compared with other composite materials manhole covers, Burglarproof manhole cover has the following specialties: Structure: Using the structure of pot bottom style (loading equally),other than the one of ribbing style (loading centrally),the strength supporting area will extend by more than ten or dozens of times. Therefore, the ability of strength sustaining will be more excellent. Materials: Our Burglarproof Artistic manhole covers (shorted for FRP manhole cover) are made from composite materials such as glass fiber, resin, quartz, corundum etc.. Applying wear-resistant and climate-resistant materials on the relief sculpture layer so that the products can be long-term used under different environment. Applying continuous reinforced fiber on the structure layer to ensure the products having sufficient sustaining ability. While some of other composite material manhole covers (for examples, BMC manhole cover) do not contain reinforced fiber, or just contain short fiber (the intensity of short fiber is 20-30% of continuous fiber); Design: Infusing the manhole covers with the art of relief sculpture, designing individually to meet clients demands with artistic effect, promoting the culture feeling of our composite material manhole cover, the material is FRP, shorted for Fiber Reinforced Plastic; FRP manhole cover material quality Our FRP products are made of: -Unsaturated polyester resin (UP) (Iso type resin, vinyl ester resin) -Glass fiber (E-glass 2400 Tex) -Quartz -Corundum -Antioxidant -Firming agent -Promoter -UV additive -Ethylene-propylene-diene-monomer -Cr13 -Other auxiliary materials Application Temperature Scope The materials used to manufacture the manhole covers are important, that is why we only use quality materials. The main material that contribute to the product application temperature is the non saturated polyester resin. It belongs to the thermosetting resin, the performance after its solidification is as follows: Longitudinal strength:250-600Mpa; Compressive strength:300-600Mpa; Stretch modulus:25-35Gpa; Break elongation ratio:1.3-10.0%; Bending strength:700-1400Mpa; Curving module:25-35Gpa; Poisson-ratio:0.35; Relative density:1.11-1.15; Water-absorptivity(24h):10-30mg; Volume resistivity.1*(1012-1014)cm Unsaturated polyester resin for the reinforced plastics uses the most universal resin, general application temperature in -40 80. If there is any special request, we may introduce a special function structure to cause its temperature to be lower or higher. When the temperature approaches-40, resin brittleness will occur. When temperature surpasses 80 for a long period of time(special heat resistant resin to be an exception) has the possibility to become soft or degrades. Therefore, our products application temperature is in the principle scope of -40 80. C250(can load 25tons) D400(can load 40tons) The Service Life From the resin heat resistance view, our products under the normal temperature uses, its service life amount to above for 50 years. The GRP manhole cover uses lamination compound craft on the surface layer between 5-8mm, where it joins the antioxidant to bear the marquis resin and it is filled by the aggregate of quartz, corundum and anti-friction materials (this kind of material is uses for the make grinding wheel). The surface of the manhole cover will not have any attrition because the designed 5-8mm provide wear resisting level extrapolation, it is possible to use above for 30 years. The compound material of the manhole covers make sure that it could withstand more than 2 million fatigue shocks. Official tests and experiments have shown any problem on the heat resistance after more than 3 years of exposure. To increase the intensity of the products, solidification craft processing is used after normal solidification process is done. Although the resin has joined with antioxidant which will delay the product from yellow stain, after a long period of time some yellow stain will still appear. It is a normal condition and does not affect the product. Our suggestion is to use color of natural stone material where only minor color change will occur.