AASHTO TP 90:2016 Standard Method of Test for Measuring Interfacial Fracture Energy of Hot-Poured Crack Sealant Using a Blister Test.
1.1. The blister test is used to determine the interfacial fracture energy (IFE) of hot-poured crack sealant at the application temperatures.
1.2. The blister test is a fracture test. The objective of the test is to apply tensile forces using hydrostatic pressure to delaminate sealant from a substrate. A thin film of sealant is poured on the top of a substrate (usually aluminum) disk that has a hole at the center. Hydrostatic pressure is applied through this hole at a constant flow rate causing delamination between the sealant film and substrate. Sealant deformation and applied hydrostatic pressure are recorded as a function of time. The amount of energy required to achieve complete delamination is called interfacial fracture energy and can be calculated from the pressure-deformation curve. This energy is considered a measure of bonding potential.
4. SUMMARY OF METHOD
Crack sealant material is homogenized following the procedure given in ASTM D5 167. For each test, including four replicates, cut 320 g of sealant and heat to the manufacturer’s recommended pouring temperature. Sealant will be poured in the mold assembled on top of an annular-shaped disk of substrate. An aluminum plug will be inserted into the hole of the substrate to close it. The sealant will be poured on top of the plugged substrate to provide a film of 4.6-mm thickness. Hydrostatic pressure is applied through the hole to cause delamination between the sealant film and the substrate. Sealant deformations and applied hydrostatic pressure can be recorded as a function of time. The amount of energy required for complete delamination is called interfacial fracture energy and can be calculated from the pressure-deformation curve. This energy can be considered an indication of bonding potential.
SIGNIFICANCE AND USE
This procedure is designed to measure the adhesion potential of hot-poured sealant to aggregate.
5.2. Sealants must be rehomogenized (ASTM D5167) before measuring adhesion by this method.
Modified direct tension test (DTT) machine or an equivalent system with environmental chamber and motor or screw driven actuator;
6.2. Chiller that can reach —40 ± 0.5°C;
6.3. Laboratory Oven—Any standard laboratory oven capable of producing and maintaining temperatures up to 200°C +2.0°C;
6.4. Release agent; and
6.5. Four test setups, four molds, four plugs, and four rubber bands. (See Figures 1, 2, and 3.)AASHTO TP 90 pdf download.