The adhesion test between asphalt and coarse aggregate is an important method to evaluate the bonding strength of asphalt and aggregate, which is mainly carried out by boiling method and water immersion method. The boiling method is suitable for aggregates with a particle size greater than 13.2mm, while the immersion method is used for aggregates with smaller particle sizes. These two methods ensure the quality and durability of road materials by observing the degree to which the asphalt membrane peels off after water immersion and assessing its resistance to water peeling.
Purpose and Scope of Application
The adhesion test of asphalt to coarse aggregate is mainly used to evaluate the adhesion between asphalt and aggregate surface, as well as the resistance of coarse aggregate to water peeling. This method is suitable for aggregates with a maximum particle size greater than 13.2 mm, using the boiling method, while for aggregates with a particle size less than or equal to 13.2 mm, the water immersion method is used. This test can provide an important basis for the engineering application of asphalt mixture.
Instrumentation and material requirements
Balance - weighing 500g, inductance is not more than 0.01g.
Thermostatic sink – can maintain a temperature of 80°C ±1°C.
Small container – for mixing, with a capacity of 500mL.
Beaker – 1,000 mL.
Test frames, fine wires, barbed wire and other auxiliary tools.
Test procedure for boiling method
Preparation
Five regular aggregates with a particle size between 13.2 mm and 19 mm were selected and dried in a 105°C±5°C oven after washing.
The process of the test
Tie the aggregate firmly with a fine wire, soak it in asphalt (130-150°C) for 45 seconds, take it out, and cool it for 15 minutes.
Then the aggregate was soaked in water kept slightly boiling for 3 minutes, and then put it in room temperature water after taking it out, and the peeling of the asphalt membrane was observed, and the adhesion grade was assessed according to Table T0616-1.
Water immersion test procedure
Preparation
Take 200g of aggregate with a particle size between 9.5mm and 13.2mm, also dry it in an oven at 105°C±5°C, and prepare asphalt.
The process of the test
The aggregate is heated for 1 hour, mixed evenly with asphalt and cooled for 1 hour.
The aggregate was immersed in a constant temperature tank at 80°C±1°C for 30 minutes, after which the peeling of the asphalt membrane was observed and evaluated.
Reporting & Assessment
The results of the test should detail the method used, the particle size of the aggregate, and the adhesion grade. The adhesion of asphalt to aggregate is evaluated according to different peeling area percentages. In order to improve the accuracy of the results, it is recommended that the rating be performed by more than two experienced personnel and averaged.
conclusion
The adhesion test between asphalt and coarse aggregate is an important method to ensure the water peeling resistance of asphalt mixture in engineering applications. Through standardized test procedures and accurate evaluation standards, this method provides a scientific basis for the selection and application of asphalt, and can effectively guide the construction practice.
summary
The adhesion test of asphalt and coarse aggregate provides a scientific basis for judging the applicability of aggregate in asphalt mixture. The stability of the asphalt membrane can be effectively evaluated by the reasonable choice of boiling method or water immersion method, so as to guide the design and production of asphalt mixture. Although this test has some limitations, it is still of great significance in the evaluation of asphalt-aggregate bonding capacity, and should be combined with other water damage test methods to comprehensively evaluate the performance of asphalt mixture.
