An experimental length scale investigation on viscoelastic behavior of bituminous composites: Focusing on mortar scale. (15th November 2021)

• Record Type: Journal Article
• Authors: Khodadadi, Mojtaba; Khodaii, Ali; Absi, Joseph; Fakhari Tehrani, Fateh; Hajikarimi, Pouria
• Is Part Of: Construction & building materials. Volume 308(2021)
• Publication Date: 2021-11-15
• Subjects: Mortar -- Multi-scale -- Master curve -- Cole-cole diagram -- Frequency sweep -- Cutting size -- Viscoelastic behavior; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.124766
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Using a multi-scale approach to find viscoelastic properties of three scales: mastic, mortar, and mixture. Threshold stress is evaluated to characterize linear viscoelastic properties of the mortar scale. Mortar with the cutting size of 3.35 mm has the closest behavior to the asphalt mixture with an NMAS of 19 mm. Abstract: The mortar component plays an essential role in forming different asphalt mixture distresses. The fine aggregate size affects the viscoelastic behavior of mortar. In this study, three cutting sizes of 3.35, 2.36, and 1.7 mm, on the aggregate grading curve were considered to construct the mortar scales, namely mortar (I), (II), and (III), respectively. With a unique loading mode, a frequency sweep test was performed on four different length scales, including bitumen, asphalt mastic, mortar, and asphalt mixture, to make a direct comparison through a multi-scale approach. Also, a stress sweep test was conducted to find the mortar scale's linear viscoelastic domain. The results indicate that different mortar types have variable linear viscoelastic domains. The master curves of dynamic modulus (E*) and phase angle (δ) show that adding filler to bitumen has more effect on the E* than the δ. Although scaling up from the mastic to mortar (II) causes a significant difference between the viscoelastic parameters, the results remained approximately the same. The main gap between the mixture and mentioned sub-scales is filled with mortar (I). While the Cole-Cole diagrams demonstrate that the bitumen to mortar (II) scales have the same behavior, the closest scale to the mixture is the mortar (I). Therefore, using a cutting size of 3.35 mm is recommended to fabricate mortar (for asphalt mixture with a nominal maximum aggregate size of 19 mm) instead of 2.36 mm, which was suggested in previous studies.