First, the classification of the basic types:
1.Cement foundation: The cement base price is moderate and is often used in football fields.
2.Cement stone powder foundation: the football field is applicable, characterized by short construction period, good drainage and low cost
3.Asphalt concrete foundation: asphalt foundation has two kinds of ordinary and hydrophobic, ordinary asphalt base price is cheap, is widely used in tennis courts, football fields: hydrophobic asphalt due to high cost and complex construction, only used for hockey stadium
4.Gravel hydrophobic foundation: flatness is very poor, but because of the lowest cost and good drainage, it is often chosen when funding is tight.
Second, the quality requirements
1.The asphalt foundation cannot produce cracks and uneven frost heave due to freezing. The cement foundation requires higher flatness of the foundation surface to ensure uniform thickness and uniform elasticity of the plastic surface layer. Flat slope: 8 inches in the horizontal direction, 5 inches in the longitudinal direction and 5 inches in the semicircular area.
2.The slope of the asphalt foundation: lateral <1%, longitudinal <1‰, high jump <4‰, flat slope of cement foundation: 8‰ in the horizontal direction, 5‰ in the longitudinal direction and 5‰ in the semicircular area. Both base surfaces should be flat and smooth and drained.
3. Strength and stability: It is best to use asphalt materials that do not contain wax or contain little wax, and the asphalt mixture must be fully compacted. The surface is even and solid, flat and crack-free, no squeezing, no pitting, smooth and smooth seams. After the medium-sized roller compactor is pressed, there is no significant wheel track, no soft skinning, no loose soil, and waves. In the large frozen area, it is better to add a layer of geotextile buffer layer between the asphalt layer and the gravel layer. The foundation along the edge of the drainage channel should be specially water-repellent because these areas are most prone to frost heave. The cement foundation should have a certain strength and stability. The surface is even and solid, no cracks, no rotten surface, the seam is straight and smooth, and the dicing is about 6000mm×6000mm. The mat is laminated, and the compactness is more than 95%. After the medium-sized roller compactor is pressed, there is no significant wheel track, no loose soil, no waves, and the like. Consider the expansion joints and the width is 5 mm.
4. The asphalt drainage system must discharge stagnant water two hours after heavy rain. The cement foundation must have a water-repellent layer. The water-repellent layer is made of a new PVC thick water-repellent film. The junction should be greater than 300mm and the margin margin should be greater than 150mm.
5.Maintenance period: The basic maintenance period of asphalt is more than 28 days, so that the low boiling point component of the asphalt surface can be used to ensure sufficient bonding strength between the surface layer and the foundation. The maintenance period of the cement foundation takes only 7 days.
