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

Area of Science:

• Civil Engineering
• Materials Science
• Geotechnical Engineering

Background:

• Bolivia faces limited crushed stone supply for highway projects.
• Local pebble resources are abundant but underutilized as coarse aggregate.
• Ensuring concrete durability with pebble aggregate is a key challenge.

Purpose of the Study:

• Compare performance of pebble concrete versus crushed stone concrete.
• Investigate the effect of fly ash on concrete's water permeability resistance.
• Evaluate suitability of pebble concrete for the Sucre Highway Project.

Main Methods:

• Comparative analysis of concrete properties using pebble and crushed stone aggregates.
• Assessment of aggregate characteristics: density, bulk density, void ratio, and gradation.
• Evaluation of concrete mechanical properties: compressive strength, flexural tensile strength, and splitting tensile strength.
• Water permeability tests on concrete incorporating fly ash.

Main Results:

• Pebbles exhibit lower density and higher void ratio than crushed stone, with dispersed gradation.
• Aggregate type significantly impacts splitting tensile strength; failure modes include slurry cracking, aggregate crushing, and interface debonding.
• Aggregate and fly ash minimally affect compressive strength but significantly influence flexural tensile strength.
• All concrete types meet traffic load requirements; fly ash enhances impermeability, mitigating aggregate-related issues.

Conclusions:

• Pebble concrete demonstrates acceptable mechanical properties and durability for highway applications.
• Fly ash addition improves concrete's water permeability resistance, addressing aggregate-related concerns.
• The study supports the viable use of local pebble resources as coarse aggregate in Bolivian highway construction.