UFC 3-260-02

30 June 2001

APPENDIX H

PROCEDURE FOR DETERMINING THE DYNAMIC MODULUS

OF BITUMINOUS CONCRETE MIXTURES

H-1. GENERAL. The purpose of this procedure is to determine dynamic modulus values of

bituminous concrete mixtures. The procedure described covers a range of both temperature and

loading frequency. The minimum recommended test series consists of testing at 4.5, 21, and

37.8 degrees Celsius (40, 70, and 100 degrees Fahrenheit) at loading frequencies of 2 and

10 hertz for each temperature. The method is applicable to bituminous paving mixtures similar to

the 25.4, 19, 12.7, and 9.5 millimeter (1-, 3/4-, 1/2-, and 3/8-inch), and No. 4 mixes as defined

by Table 3 of ASTM D 3515.

H-2. APPLICABLE STANDARDS. The following ASTM standards are applicable to this procedure:

C 617, D 1559, D 1561, and D 3515.

H-3. SUMMARY PROCEDURE. The dynamic modulus test is run by applying a sinusoidal

(haversine) axial compressive stress to a specimen of bituminous concrete at a given temperature

and loading frequency. The resulting recoverable axial strain response of the specimen is measured

and used to calculate the dynamic modulus.

H-4. DEFINITIONS. The following terms are used in this procedure:

a. Dynamic Modulus. The absolute value of the complex modulus which defines the elastic

properties of a linear viscoelastic material subjected to a sinusoidal loading.

b. Complex Modulus. A complex number which defines the relationship between stress and

strain for a linear viscoelastic material.

c. Linear material. A material whose stress-to-strain ratio is independent of the loading stress

applied.

H-5. APPARATUS. An electrohydraulic testing machine with a frequency generator capable of

producing a haversine wave form has proven to be most suitable for use in dynamic modulus

testing. The testing machine should have the capability of applying loads over a range of

frequencies from 1 to 20 hertz and stress levels up to 0.69 MPa (100 psi). The temperature

control system should be capable of a temperature range of 0.0 to 49 degrees Celsius (32 to

120 degrees Fahrenheit). The temperature chamber should be large enough to hold six specimens.

A hardened steel disk with a diameter equal to that of the test specimen should be used to transfer

the load from the testing machine to the specimen.

H-6. SPECIMENS. The laboratory-molded specimens should be prepared according to Appendix H.

A minimum of three specimens is required for testing. The molding procedure is as follows: Cap all

specimens with a sulfur mortar meeting ASTM C 617 requirements prior to testing. Bond the

strain gauges with epoxy cement to the sides of the specimen near midheight in position to

measure axial strains. (Baldwin Lima Hamilton EPY 150 Epoxy Cement has been found satisfactory

for this purpose. On specimens with large-size aggregate, care must be taken so that the gauges

H-1

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