Structurally integrated cement stabilized gravel base layer or subbase layer design method

Abstract

The invention discloses a structurally integrated cement stabilized gravel base layer or subbase layer design method. The method includes steps: working out a pavement structure combination; establishing a calculation model, and determining an age and modulus of each structural layer in the model; calculating a bottom layer tensile stress of a cement stabilized gravel base layer or subbase layer; determining a 7d compressive strength design standard [Rc7] and a 7d splitting strength design standard [Rs7]; designing mineral aggregate gradation; determining a maximum dry density Rhomax and an optimum water content wo of a cement stabilized gravel mixture material; testing a 7d unconfined compressive strength Rc7 and a 7d splitting strength Rs7, and determining a cement addition quantity which meets requirements that Rc7 is larger than or equal to [Rc7] and Rs7 is larger than or equal to [Rs7], so that designing is completed. The method has advantages of low input cost, simplicity and convenience in use and operation, great utilization effects and effectiveness in solving of problems of disjunction with pavement structures and proneness to shrinkage cracking of existing cement stabilized gravel design.

Description

technical field [0001] The invention relates to the field of traffic civil engineering, in particular to a design method for a cement-stabilized crushed gravel base or sub-base integrated with a structure. Background technique [0002] Crushed gravel or gravel is the main material for building road pavement bases. Compared with crushed gravel, broken gravel has fewer broken surfaces, smooth surfaces, and poor angularity, resulting in relatively low strength of cement-stabilized broken gravel and easy segregation. In order to increase the strength of cement to stabilize broken gravel and reduce segregation, increasing the cement dosage and adopting finer gradation have become the most common technical means in engineering practice. It is almost a consensus that the cement dosage should reach more than 4-6%. However, the consequence is that the cement-stabilized broken gravel base or the sub-base has serious shrinkage cracks, and other damages such as pumping and network crack...

AI Technical Summary

Problems solved by technology

Due to the low strength of cement-stabilized crushed gravel, it is almost the only means to ensure that the cement-stabilized crushed gravel meets the above-mentioned strength standards by increasing the dosage of cement. Increasing the amount of cement will cause serious shrinkage of the base or subbase of cement-stabilized crushed gravel Cracking will affect the service life of the pavement; (2) In the traditional design method, the splitting strength, modulus and tensile strength structure coefficient of cement stabilized macadam are pavement structural design parameters, while the only index for mixture design is 7d without side Therefore, the material performance requirements of the pavement structure cannot be considered in the design of the mixture, and the structure and material design are out of touch, so that the designed mixture cannot effectively control cracking

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