![]() Shown, most of the validated data are located fairly close to The crack propagation model using the LOOCV method. Figure 4.12 (b) presents the validation of Mate of 0.59, and Mallowâs Cp of 6.0, indicating good pre-ĭiction quality. This model gives a R2 of 0.85, a standard error of the esti. Validation: (a) relationship between predicted and field-measured longitudinalĬracking and (b) validation of the longitudinal cracking model. Wheel-path longitudinal cracking statistical model development and Predictor variables and their ranges of wheel-pathįigure 4.12. ![]() #200 sieve could result in a more flexible and less crack sus-įigure 4.12 (a) shows the relationship between predictedĪnd field-measured wheel-path longitudinal crack length.ĭynamic modulus, 70Â☏, 1Hz MPa 706.3-8448.1 Traffic load (AADTT) can lead to more crack propagation Īnd (e) within a specific range, a higher percent passing the Top-down cracking (AASHTO 2008) (d) increased truck (c) the pavement with higher in-place air voids may have more Values could be related to high stiffness and high brittleness,Īnd would therefore be more prone to top-down cracking 2010) (b) overlay mixtures with high IDT strength Potential to develop top-down longitudinal cracking (RoqueĮt al. With a thicker pavement structure generally have a higher The effects of individual predictor variables are in goodĪgreement with the literature findings: (a) the pavements X5 = percentage passing the #200 sieve, %. Y = field longitudinal cracking, ft/200 ft Į = base of natural logarithm, approximately 2.718 With low levels of top-down crack distress and vice versa. A negative trend indicates that high values correlate Ues correlate with high levels of top-down crack distress and A positive trend indicates that high val. Parentheses indicates the trend between the predictor vari-Ībles and responses. (+), and percentage passing the #200 sieve (-). Thickness (+), IDT strength (+), in-place air voids (+), AADTT Five parameters were selected: total pavement Longitudinal cracking ranking based on the second-round distressĭevelopment. Number of HMA-WMA pairs that have consistent Longitudinal cracking ranking based on the first-round distressįigure 4.11. Rankings between material property ranking and wheel-path Of wheel-path longitudinal cracking using the PLS method.Īppendix G provides detailed methodology about the modelįigure 4.10. Table 4.1 contains predictor variables and the ranges ofĮach independent variable measured during this project.Įquation (4.1) presents the model for predicting the length Temperature hours, AADTT, and pavement age. ¢ Climate, traffic, and pavement age parameters: room. ¢ Pavement structure: total HMA thickness and overlay ¢ Binder properties: G*sind, binder fracture energy, and Modulus at 70Â☏ and 1 Hz in-place air voids aggregate ¢ Mixture properties: IDT strength at 68Â☏ fracture workĭensity at 68Â☏ mixture fracture energy at 68Â☏ dynamic The following factors wereĬonsidered for the model based on literature findings: The PLS method was applied to develop a predictive wheel. In terms of crack length based on the second-round distress survey results. Wheel-path longitudinal cracking comparisons among WMA additives (c) Comparison Between Organic and Foamingįigure 4.9. That the WMA pavement had more wheel-path longitudinalĬracking than the HMA pavement: the MO Hall St. Ments show longitudinal crack lengths that are comparable Rable.â Figure 4.2 (b) indicates that, as a whole, the HMA pave. ![]() HMA-WMA pairs within the project are treated as âcompa. For those proj-Įcts that did not exhibit wheel-path longitudinal cracking, the The first-round wheel-path longitudinal crackingĬomparison includes 41 HMA-WMA pairs. Ure 4.2 (a) shows that eight projects exhibited longitudinalĬracking. Pavement comparisons in terms of wheel-path longitudinalĬracking based on the first-round distress survey results. This section presents a summary of the HMA versus WMA It is noted that bottom-upįatigue cracking was not identified at any field sites evaluated On field cores extracted from the tip of wheel-path longitu-ĭinal cracks, such longitudinal cracks in the wheel-path typi-Ĭally are top-down fatigue cracks. Mally 2 to 4 ft away from the shoulder or centerline. This chapter focuses on wheel-path longitudinal cracking ![]() Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages. Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book.
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