Experimental Research On Crack Resistance Cement-Stabilized Sand Gravel Base Material

The cement-stabilized gravel base materials have been extensively used in base paving, the pavement with cement-stabilized gravel base, as the other semi-rigid base, easily product cracks. In order to prevent or delay the cracks, according to the dense framework structure gradation range is proposed by regarding cement-stabilized macadam as the research object in Specifications for Design of Highway Asphalt Pavement JTG D50-2006,natural gravel is regarded as the research object in this paper, the method of combining step filling test and theoretical calculation I method is introduced to determine dense framework structure mixture gradation of cement-stabilized gravel, a supplement of dense framework structure of cement-stabilized aggregate gradation is made. The composition structure types of cement-stabilized gravel base were classified by adopting the passing rate of 4.75mm after proposed the dense framework structure gradation range. Then the strength and stiffness characteristics of cement-stabilized gravel mixture were studied with different composition structure types and different cement dosages ,cement -stabilized gravel base materials drying shrinkage test were carried out by using bracket method; cement-stabilized gravel base materials temperature shrinkage test were carried out by using resistance strain-gauge testing method. The results showed that with the cement dosages increased, the average dry shrinkage coefficient of cement-stabilized gravel course materials increased; the average temperature shrinkage coefficient of cement-stabilized gravel course materials decreased first and then increased. In three composition structure types, the dry shrinkage crack resistance order is GK >GM >XM; temperature shrinkage crack resistance order is GM>GK >XM. According to test results, the cement-stabilized gravel base materials mix proportion with good mechanical property and crack resistance were determined, the design parameters recommended value of cement-stabilized gravel base materials was proposed.