The base should be constructed under the following requirements: The surface should be turtle shape, with a slop of 0.4%-0.6% ² be stable
² certain tensile strength
² without crack and wave
² density should be 90%
² without frost-heaving or freezing situation caused by humid
² surface flat requirements: the qualified rate should more than 95%, the unevenness cannot exceed 4mm within 3m length of a straight course in any direction
