Performance Evaluation of Pebble Concrete for Pavement: A Study on the Sucre Highway Project

Bolivia has abundant pebbles, while the supply of crushed stone is limited and unstable. Thus, the resource utilization of local pebble as a coarse aggregate and the guarantee of concrete durability are the key scientific issues in the Sucre Highway Project. In this paper, a comparative analysis was conducted of the performance of crushed stone concrete and pebble concrete. Additionally, the impact of fly ash on the water permeability resistance of concrete was investigated. The results indicate that the apparent density, bulk density, and void ratio of pebbles are lower than those of crushed stone, and the aggregate gradation of pebbles is dispersed. The type of aggregate is the primary factor influencing the splitting tensile strength of concrete, with the main failure modes of pebble concrete being slurry cracking, aggregate crushing, and interface debonding. While aggregate and fly ash have a minor effect on compressive strength, they significantly impact flexural tensile strength; however, all concretes meet the requirements for extra-heavy, very heavy, and heavy traffic load levels. In terms of impermeability, fly ash effectively mitigates the negative impact of aggregate type on the impermeability of concrete. These findings support the application of pebble concrete in the highway project.