Analytic Study Of The Effect Of Interface State On The Strength Of Bituminous Mixture

Unconfined compressive strength test is one of the most important way to evaluate pavement material properties, which results directly affect the accuracy and rationality of the results of pavement structure and material design. Found in previous tests, specimen end effects will inevitably be the effects of friction, and the mixture strength of specimen destruction and damage are different in different end-state. This paper studies and interprets the differences of the compressive strength and the failure mode of destruction in the different end-state.Tests show the different compressive strength in diameter height ratio of 1:1 asphalt mixture specimens which are end untreated and wax to seal the deal. We discover the ratio of the latter with the former is 0.5～0.9, and the two failure modes are very different. The representative horizontal and vertical fields obtained simultaneous based on digital image measurement explain the differences of forms of damage under three different end-states. We compare of the differences in the average vertical strain with a narrower range of local under three groups different specimens conditions, diameter height ratio of 1:1 asphalt mixture specimens which are of specification and end untreated,diameter height ratio of 1:1 asphalt mixture specimens which are wax to seal the deal and diameter height ratio of 1:1.5 asphalt mixture specimens which are end untreated. We discover that the latter two states can better reflect the true stress-strain relationship than the former. Compared of the three compressive strength values, we discover that the compressive strength value in diameter height ratio of 1:1 asphalt mixture specimens which are wax to seal the deal is more conservative. So we recognize the diameter height ratio of 1:1 asphalt mixture specimens which are wax to seal the deal is more suitable for unconfined compressive strength tests. Based on the finite element analysis, we carry out numerical simulation on explaining the differences of compressive strength test values and the failure modes of numerical simulation are basically the same as the test specimen failure modes.