Mechanical Properties of Concrete Pavement Mixtures with Larger Size Coarse Aggregate

The use of larger maximum size aggregates (MSA) in concrete mixtures can increase the load transfer efficiency across aggregate interlock joints if small crack widths are achieved. Aggregate interlock joints can minimize the number of dowels required on airport and low volume concrete pavements, and thus decrease their total construction cost. This paper describes a laboratory study evaluating the strength, fracture, and shrinkage properties of airport concrete mixtures with 1 and 1.5 inch MSA and several total cementitious contents. Although the split tensile and flexural strength of the larger MSA mixtures were reduced by 20 percent, the 28-day fracture energy was similar between the mixtures. The 1-day GF was significantly greater for the larger MSA mixture indicating a greater joint shear transfer capability. The brittleness of the concrete was also reduced as the MSA increased. Finally, the concrete free shrinkage was similar for the same mix proportions but different MSA.