Framework structure design based on porous permeable concrete material in expressway tunnel drainage system

As an important construction material for drainage system construction, permeable concrete has the characteristics of porous and breathable, but the existing mix preparation technology makes it difficult to prepare high-strength porous permeable concrete material. The study introduces a permeable concrete skeleton structure that considers compressive strength and permeability coefficient. Moreover, the proportion design method is adjusted based on the spherical characteristics of the aggregates, which are analyzed using Image Pro-Plus image processing technology. The parameters of the permeable concrete skeleton structure, such as the number of contact points, width of the contact zone, and thickness of the inter-aggregate slurry, are quantified. Additionally, the proportion design method is refined by incorporating the target mechanical properties and water permeability performance of the permeable concrete, aiming to enhance its mechanical properties and water permeability. To enhance the mechanical properties and water permeability of pervious concrete, modifications are made to the proportion design method based on target mechanical properties and water permeability. This includes balancing the mechanical properties and water permeability through the design of the concrete's skeleton structure, the composition of the cement slurry, and the adjustment of additive mixing amounts. The use of a single-graded pyrophyllite aggregate enables the preparation of high-strength and high-permeability concrete. The experiment showed that the minimum deviation of compressive strength of group A was 15.29%, the average was 18.17%, and the minimum deviation of compressive strength of group B was 42.59%, the average was 45.27%. The minimum deviation of the water permeability coefficient in group A was 10.60%, with an average of 16.50%, and the minimum deviation of the water permeability coefficient in group B was 11.35%, with an average of 19.18%. In addition, the correction coefficient relationship between aggregate sphericity and the number of contact points, contact zone width and paste thickness between aggregates was established. Through the correction of the coefficient, the high strength, and high permeability concrete with permeability coefficient, compressive strength, and effective porosity of 1.15, 23.6mpa, and 18.5% can be obtained. The mix proportion design of permeable concrete using a skeleton structure in this study has economic and social benefits for