Fatigue Resistance and Cracking Mechanism of Semi-Flexible Pavement Mixture

Abstract

Semi-flexible pavement (SFP) is widely used in recent years because of its good rutting resistance, but it is easy to crack under traffic loads. A large number of studies are aimed at improving its crack resistance. However, the understanding of its fatigue resistance and fatigue-cracking mechanism is limited. Therefore, the semi-circular bending (SCB) fatigue test is used to evaluate the fatigue resistance of the SFP mixture. SCB fatigue tests under different temperature values and stress ratio were used to characterize the fatigue life of the SFP mixture, and its laboratory fatigue prediction model was established. The distribution of various phases of the SFP mixture in the fracture surface was analyzed by digital image processing technology, and its fatigue cracking mechanism was analyzed. The results show that the SFP mixture has better fatigue resistance under low temperature and low stress ratio, while its fatigue resistance under other environmental and load conditions is worse than that of asphalt mixture. The main reason for the poor fatigue resistance of the SFP mixture is the poor deformation capacity and low strength of grouting materials. Furthermore, the performance difference between grouting material and the asphalt binder is large, which leads to the difference of fatigue cracking mechanism of the SFP mixture under different conditions. Under the fatigue load, the weak position of the SFP mixture at a low temperature is asphalt binder and its interface with other materials, while at medium and high temperatures, the weak position of the SFP mixture is inside the grouting material. The research provides a basis for the calculation of the service life of the SFP structure, provides a reference for the improvement direction of the SFP mixture composition and internal structure.

Improvement of the Low-Temperature Cracking and Shear Resistance of Semi-Flexible Mixture Modified by Polymers

“…Semi-flexible pavement refers to a pavement that combines the advantages of cement concrete pavement and asphalt concrete pavement by filling cementitious grouting material into large pore matrix asphalt mixture. Its high-temperature stability and water stability are generally better than ordinary asphalt concrete pavement, and its fatigue resistance and low-temperature crack resistance are also greatly improved than ordinary cement concrete pavement [1][2][3][4]. The matrix asphalt mixture and cement grouting material, as the main compositions of semi-flexible pavement materials, have great differences in mechanical properties.…”

Study of the Effect of Grouting Material Strength on Semiflexible Pavement Material

“…Numerous studies on SFP materials have shown the superior high-temperature stability and low-temperature cracking resistance of SFP materials in comparison with conventional asphalt mixtures. Wang et al [6] used crack resistance tests to assess the crack resistance of SFP mixtures under diferent temperature conditions, and the results showed that SFP mixtures have better crack resistance at low temperatures. Hou et al [7] investigated the mechanical properties and durability of SFP materials and verifed that their high-temperature stability, fatigue performance, and water stability were signifcantly better than those of typical asphalt mixtures.…”

“…However, the efect of the strength of the grouting material on the compressive strength of SFP material was not illustrated in this experiment. Wang et al [6] investigated the efect of grouting material with a strength of 15.8 MPa on the fatigue performance of the SFP material and compared it with conventional asphalt concrete (AC). Te results showed that the fatigue resistance of the SFP material was signifcantly lower than that of AC under low-temperature and high-stress ratio conditions, but the addition of grouting material was not shown to have a positive efect on the fatigue resistance of the SFP material in this experiment.…”

“…Te performance of the SFP materials can be improved by injecting grouting materials of diferent strengths, as indicated above, but there are still some issues that need to be addressed. Cai et al [22], Wang et al [6], Cai et al [23], and other scholars in their studies selected the grouting materials of single strengths, leading to a lack of comparability in the efects of diferent grouting material strengths on the SFP material performance. Te diference between the grouting material strengths chosen by Wang et al [25], Fang et al [28], and Imran Khan and Hartadi Sutanto [29] is not signifcant, and as a result, the improvements in the SFP material performance are not obvious, failing to obtain the substantial change pattern of the grouting material strength's infuence on the performance of SFP materials.…”

Evaluation of the Contribution Rates of Different Phases on Pavement Performance of Cement-Casting Asphalt Mixture

“…Cement-casting asphalt mixture has drawn great attention during the past several years in both research and application elds in China [1][2][3][4][5]. It has been widely utilized to address the severe rutting distress of asphalt pavement in heavy-duty sections, such as intersections, BRT lanes, and bus stops [6].…”