How the Mix Factors Affect the Dynamic Modulus of Hot-Mix Asphalt

Abstract

Hot-mix asphalt (HMA) is a composite material consisting of stone-aggregates, sand, asphalt binder and additives. The properties of this combined material are dependent on the volumetric parameters used in the mix design. This study investigates the effects of volumetric mix factors on the dynamic moduli (E*) of eleven categories of HMAs. For each category of asphalt mixture, the variations in dynamic modulus for different contractors, binder types, effective binder content (Vbe), air void (Va), voids-in-mineral aggregates (VMA), voids-filled-with asphalt (VFA) and asphalt content (AC) are assessed statistically. Results show that the S(100) mixture (nominal size of 19 mm, 100 gyrations) with the Performance Grade (PG) binder of PG 64-22 has the highest value of E* at low temperature or high reduced frequency. At high temperature or lower reduced frequency, S(100) PG 76-28 has the highest E* value. The SX(75) mixture (nominal size of 12.5 mm, 75 gyrations) with the binder of PG 64-28 has the lowest E* value at high temperature or lower reduced frequency. At low temperature or high reduced frequency, SX(75) PG 58-34 has the lowest E* value. The Stone Mix Asphalt (SMA) mix has a lower E* compared to S(100) and SX(100) mixes ((nominal size of 12.5 mm, 100 gyrations) with the Performance Grade (PG) binder of) at low temperature. The E* increases with an increase in Vbe, Va, and VFA, and decreases with an increase in VMA and AC. The E* of a mix can vary from 200 ksi (1380 MPa) to about 1000 ksi (6900 MPa) for a particular frequency (10 Hz) and temperature (21.1 °C), even if samples are from the same contractor.

Comparative Study of Hot Asphalt Mixtures Properties Designed by Marshall and Superpave Methods. (Dept. C)

“…The used aggregate gradation was similar to sample (B2). This gradation was compared to the Superpave control points and restricted zone as shown in figure (15). (4) Mix Design Procedures Initial Blend: Three samples were prepared using the aggregate gradation with the chosen initial asphalt content (P bi ) which was 5%.…”

“…After the Superpave design was completed and the OAC was determined, a new sample was compacted using the gyratory compactor to (N Max = 160) in order to be tested by the Marshall Stability and Flow device [11]. And the results are illustrated in table (15)…”

Study on the Influence Factors of the Dynamic Property of the Polyurethane Mixture with Dense Gradation

“…The dynamic modulus was found to depend on variables such as the aggregate gradation, asphalt binder type, aging degree, and volume parameters [25][26][27][28][29][30][31][32]. Islam et al [33] confirmed the aforementioned conclusion that the dynamic modulus would increase as the effective asphalt content, air void, and void-filled asphalt content increased, while it would decrease as voids-mineral aggregate and asphalt content increased. Zhang et al [34] discovered that the porous asphalt (PA) mixture's dynamic modulus decreased as the air voids increased, with and without moisture conditioning.…”

“…As air voids increased, the dynamic modulus degradation of the asphalt mixtures subjected to various freeze-thaw moisture conditioning times would increase [10]. The factors impacting the dynamic modulus of the high-modulus asphalt mixture were studied [33]. The asphalt binder properties could significantly affect the performance and the inherent uncertainty of the asphalt mixture [37].…”

Dynamic Modulus Prediction of a High‐Modulus Asphalt Mixture

“…Lu et al [6] compared and analyzed the dynamic modulus of the high-modulus asphalt mixture and SBS-modified asphalt mixture. Islam et al [7] studied the influencing factors of the dynamic modulus of the high-modulus asphalt mixture. However, since most of the equipment used in dynamic modulus tests is imported products, there are problems such as expensive equipment and high test costs.…”