Concept of Film Thickness Applied to a New Approach for Polymer Concrete Mix Design for Airport Pavement Repair

Because of its superior ability to bond to substrate materials and its good resistance to freezing and thawing cycles, polymer concrete has been widely used for repairing airfield pavements. However, polymer concretes used in repairing airport pavements in South Korea have not lasted as long as originally predicted; this premature failure may be attributable to the incompatibility of the coefficient of thermal expansion (CTE) between the polymer concrete and the substrate concrete material. To lower the CTE of the polymer concrete, the amount of polymer must be decreased and the amount of coarse aggregates increased. To determine the optimum amounts of polymer and coarse aggregates, a new concept of film thickness is proposed. In this research, the laboratory evaluation was performed on the mixtures of polymer concrete to measure compressive strength and CTE. On the basis of these test results, it was discovered that a larger amount of coarse aggregates lowered the CTE value and increased the film thickness; these changes resulted in a higher compressive strength than that of a typical polymer concrete with fine aggregates. As expected, the CTE of the polymer concrete decreased as the amount of polymer decreased. On the basis of limited laboratory test results, a film thickness of 33.5 Μm is recommended to satisfy the minimum requirement of compressive strength (21 MPa) for repair material in South Korea. This minimum film thickness can be achieved with a mix of 8.2% polymer and 91.8% sand. However, if coarse aggregates are substituted for 40% of the sand, the same film thickness can be maintained if the amount of polymer is reduced to 6.35%.