This figure demonstrates that changes in the measure of bitumen content create sizable differences in the stiffness modulus of asphaltic samples that include waste glass cullet. As the percentage of glass increases, the measure of the stiffness modulus of modified asphalt increases too. But with pass of optimum measure of glass the stiffness modulus of asphaltic samples decrease. This trend in total of percentages of bitumen content is existing. Due to that waste glass cullet has no suction; the trend does not extend to measuring the stiffness modulus of asphaltic samples including waste glass cullet with different percentage of bitumen content. Glass particles do not absorb any bituminous material, so it is necessary to decrease the bitumen content with the addition of glass cullet. According to Fig. 2 and the results of the Marshall tests, the optimum bitumen measures decrease significantly in samples that include higher percentages of waste glass cullet. As the percentage of optimum bitumen content is 1% more in samples without waste glass cullet in comparison with saphaltic samples that include 20% waste glass cullet. The stiffness modulus of asphaltic samples that include waste glass cullet increased due to additional interlocking between the aggregate and the angularity of particles of glass cullet content. The increase in the intrusive friction angle because of the glass particles’ increased angularity is the main reason for the addition of the stiffness modulus of asphaltic samples that include waste glass cullet. But as the percentage of glass content reaches greater than 15%, the particles’ abundance cause slip these particles on together. The stiffness modulus of samples decreases as the percentage of glass cullet increases. The variations in the stiffness modulus of asphaltic samples that include different percentages of waste glass cullet at different temperature are shown in Fig. 3.
