Highway Research Record

II. PAVEMENT ENGINEERING AND PAVING MATERIALS
2. FLEXIBLE PAVEMENT
NEW PROJECTS
Evaluation of Resilient Modulus of Bituminous Mixtures as per ASTM D 4123 Procedure

Date of Start: August 2004 to March 2005
Larsen and Toubro Limited, ECC Division, Chennai. (R, S, I)

Scope and Objectives
(i) IRC: 37 – 2001 provides the design guidelines for flexible pavement based on empirical approach. However, the mechanistic design approach is more realistic.
(ii) The modulus is dependent upon stress, strain and load cycles. ASTM D - 4123 provides the test procedure to evaluate elastic properties of asphalt mixtures.

Methodology

(i) Test samples of size 101.6 mm diameter and 63 mm height were prepared as per ASTM D -1559.
(ii) Optimum grading and bitumen content were derived according to the MS 2 of asphalt Institute guidelines. The samples     were prepared with bitumen of grade 60/70, CRMB and PMB - 40.
(iii) A servo controlled universal testing machine was used to simulate the cyclic load of 1Hz frequency with the load duration of      0.1 sec.

Conclusions

(i) The resilient modulus values of samples with bitumen 60/70, CRMB and PMB - 40 are in the range of 3650, 4500 and 7000      M Pa respectively.
(ii) The elastic modulus values given in IRC: 37-2001 are based on the test conducted at IIT, Kharagpur. The test procedure is      different from that of ASTM D - 4123.The resilient modulus values derived from the test results are observed to be higher      than the values specified in the IRC:37-2001.