Study on the antifreeze performance of porous cement stabilized macadam

The internal drainage of roads is one of the most important measures to prevent water accumulation, especially on rainy days. Porous cement stabilized macadam is widely used as a skeleton porous material because of its excellent performance in road bases. So far, many scholars have researched the design and pavement performance of Porous cement stabilized macadam. However, minimal research has focused on the permeability and mechanical properties of Porous cement stabilized macadam materials subjected to freeze - thawing cycles in freezing areas. In this paper, through an indoor equivalent freeze–thawing cycle test, the effect of freezing and thawing cycles on the permeability performance and mechanical properties of two test groups was studied: a wet-frozen freeze–thawing test group and a water-immersion-frozen freeze–thawing test group. The changes in the void ratio, unconfined compressive strength, indirect tension strength, and compressive modulus of the resilience after repeated freeze–thawing cycles were examined. And the effects of the freeze–thawing cycles on permeability performance and mechanical properties under different conditions were evaluated. The experiment identified a minimal freeze–thawing cycle effect on the permeability performance of the porous cement stabilized macadam materials, for which the maximum increase in void ratio did not exceed 1.3%. However, it was bring the greater impact on the mechanical properties of the porous cement stabilized macadam after freeze–thawing cycle test. Unconfined compressive strength and indirect tension strength were reduced by a maximum of 37.94% and 53.49%, respectively, and the freeze–thawing cycle under saturated water conditions exhibited the greatest influence on the properties of the porous cement stabilized macadam as well as the unconfined compressive strength of the sample subjected to the water-immersion-frozen freeze–thawing test groups and wet-frozen freeze–thawing test groups. The unconfined compressive strength of the specimen was reduced by a maximum of 15.09%, whereas the indirect tension strength was relatively decreased by 28.57%. In addition, according to the test data to fit the corresponding function equations, it is proposed targeted improvement measures to provide theoretical guidance for practical engineering applications.