A simplified technique for measuring dynamic modulus of asphalt concrete

Abstract EN

Measuring dynamic modulus of asphalt mixes is becoming more important for pavement design.

There are different methods for measuring dynamic modulus of asphalt mixes by using complicated dynamic equipments, not available in Egypt.

Recently, the plastometer apparatus has been manufactured in Egypt and successfully used for measuring dynamic modulus (Ed) of asphalt mixes.

Yet, this apparatus has not widely used in highway laboratories because its specimen differs in shape and preparing method from Marshall procedure.

So, this study aims at simplifying the method of obtaining dynamic modulus of asphalt mixes by conducting the simple static indirect tensile test (ITT) on Marshall specimen in traditional highway laboratories.

Quantifying the effects of aggregate gradation, asphalt content and compaction effort on the measured dynamic modulus is another objective.

To achieve these objectives, two major tests were conducted on different asphalt mixes with varying three aggregate gradations, five asphalt contents and three compacting efforts.

The conducted tests are plastometer and ITT, which were used for measuring dynamic modulus (Ed) and static elasticity modulus (Es) of paving mixes, respectively.

Statistical analysis of the two test results showed that a good estimate of Ed can be obtained from the results of ITT at various mix conditions, using the developed equation.

Finally, the study recommends to use coarse aggregate gradation in paving mixes under firm control on asphalt content and compaction for superior field performance of these mixes.