Crack resistance of fiber‐reinforced asphalt mixtures: Effect of test specimen and test condition

Abstract

The effect of some important testing conditions including test specimen (SCB and ENDB), fracture mode (I and II), loading rate (0.5, 1.0, and 5.0 mm/min), and temperature (−5°C, −15°C, and −25°C) is evaluated on fracture toughness of asphalt material containing different percentages of fibers (0%, 0.025%, 0.05%, and 0.1% of unit weight). The experimental and numerical results show that the addition of 0.025%, 0.05%, and 0.1% of the polyolefin–aramid fiber in asphalt mixture increases the fracture toughness of the control mixture by about 8%, 17%, and 23% in pure mode I and 7%, 16%, and 24% in pure mode II, respectively; which are among the most promising enhancements compared to other fibers. Results also reveal that fracture toughness at mode I obtained from the SCB and ENDB specimens is similar. However, the mode II fracture toughness obtained from the ENDB specimen is about 12% higher than the corresponding value obtained from the SCB specimen.

A study on the influences of a hygrothermal environment on the compressive strength and failure criteria of asphalt mixtures based on true triaxial tests

“…The other is that the lateral pressure increases proportionally, and the design stress ratios α = α 1 :α 2 :α 3 are 0.1:0.25:1; 0.1:0.5:1; 0.1:0.75:1 and 0.1:1:1. Since the asphalt mixtures are visco-elastic materials, their failure behaviour can be influence by the loading rate [ 45 , 46 , 47 ]. Under the combined action of different temperature and loading rate, the fracture energy of asphalt mixture will change greatly [ 48 ].…”

Influence of testing method on mode II fracture toughness (KIIc) of hot mix asphalt mixtures

“…Most of the available test specimens have either cylindrical or rectangular beam shapes. [8][9][10][11][12][13][14][15] This is because making laboratory test sample in the mentioned geometries is easier than other geometries and shapes for asphalt mixtures. Center cracked circular disc (CCCD) specimen subjected to compression diametral force (often known as Brazilian disc), 16,17 semi-circular bend (SCB) specimen containing either vertical or inclined edge crack, [18][19][20][21][22][23][24][25][26][27] edge notch disc bend (ENDB) specimen, [28][29][30][31][32][33][34][35][36] and disc specimen weakened by U-notch 37 are among the circular shape test samples in this regard that are able to introduce both mode I and mode II deformations in asphaltic samples.…”

Mixed mode I+II fracture parameters and cracking trajectory of heterogeneous multilayer pavement structure containing reflective crack

“…In recent years, several researchers have used different laboratory tests including the semicircular bending (SCB) test, 20–28 the dissipated creep strain energy (DCSE) test, 29 the disc‐shaped compact tension (DCT) test, 30,31 the edge notch disc bend (ENDB) test, 32–39 and so on 40,41 for investigating and analyzing the fracture behavior of asphalt mixtures. However, many of these laboratory tests cannot simulate exactly the cracking mechanism of real asphalt mixture in the field 23,36,42–53 . On the other hand, employment of laboratory samples in the real scale of pavement layers and subjected to actual traffic loading is impossible or at least is a very expensive and time‐consuming process.…”

“…However, many of these laboratory tests cannot simulate exactly the cracking mechanism of real asphalt mixture in the field. 23,36,[42][43][44][45][46][47][48][49][50][51][52][53] On the other hand, employment of laboratory samples in the real scale of pavement layers and subjected to actual traffic loading is impossible or at least is a very expensive and time-consuming process. Therefore, utilizing numerical analyses can be used as a suitable method to study the fracture behavior of the cracked asphalt pavement.…”