Mechanism, prevention and remedy of alkali-pumping in new constructed asphalt pavement

Backcalculation of Thickness and Dielectric Properties of Asphalt Concrete Using Numerical Simulation of Ground Penetrating Radar

“…For an AC pavement with three lifts and 5 years of field aging under the desert-like conditions of New Mexico, dielectric constants vary from 2.8 to 4, with higher values at the bottom. The results from this study are also comparable with those of previous studies, as they report dielectric property variations in AC between 2 and 4 ( 27 – 29 ). Moreover, previous studies also demonstrated that whenever the value of the dielectric constant reduces considerably in a particular location from the surrounding average, this generally indicates possible distress in that location ( 16 , 24 , 28 , 30 ).…”

“…The results from this study are also comparable with those of previous studies, as they report dielectric property variations in AC between 2 and 4 (27-29). Moreover, previous studies also demonstrated that whenever the value of the dielectric constant reduces considerably in a particular location from the surrounding average, this generally indicates possible distress in that location (16,24,28,30). According to those studies, the dielectric property of a layer may change, owing to the presence of moisture, foreign materials, an increase in air voids, fracture, delamination, stripping, or poor compaction.…”

Study on Crystallization Mechanism of Asphalt Mixture in Bridge Deck Pavement

“…In order to study the influence of crystal on the performance of the pavement, an infiltration test, core sample porosity test, splitting test and multi-wheel rutting test were carried out for the crystal and non-crystal area, respectively, and the performance difference between the crystal and non-crystal area was obtained. Among them, an infiltration test and core sample porosity test were used to analyze the difference in pavement compactness and study the compactness of the crystal precipitation area [33,34]. The core sample splitting test was used to explain the difference of mechanical properties, and study the influence of crystal precipitation on mechanical properties.…”

“…(a) (b) (c) Huang Zhiyong et al showed that alkaline flooding is different from asphalt, aggregate and dust flooding, cannot be washed away by high-pressure water and has a certain adhesion strength [32,33]. Li Weixiong et al carried out chemical analyses of alkaline flooding substances and found that the main substances were CaCO3, Mg(OH)2 and CaCO3 [34][35][36]. Related scholars have carried out a series of studies on the phenomenon of alkaline flooding, but crystallization has not been the focus in pavement engineering In the past, the asphalt mixture used in the bridge deck pavement often had crystals appearing after alkaline flooding, which were white or yellow water-insoluble attachments distributed in flakes or scattered spots [1][2][3].…”