Effect of Sodium Chloride on the Modulus and Fatigue Life of Bituminous Mixtures

Abstract

Bituminous mixtures are not perfectly elastic materials, so their viscoelastic properties play a decisive role in knowing their behavior. This research aims to find out this behavior through the values of the resilient modulus, the dynamic modulus, and the fatigue life for asphalt concrete and porous mixtures when they are influenced by the presence of salt (NaCl, sodium chloride). The aforementioned influence of salt has been evaluated by utilizing three different methods: submerging specimens of bituminous mixture in salt water; introducing salt into the specimens as if it was aggregate and immersing the aggregate in salt water; and drying it and then manufacturing the bituminous mixture with it. As the results indicate, the mixtures submerged in salt water do not show large differences in comparison to the reference mixtures for hot mix asphalt and porous mixtures. However, for hot mix asphalt in which salt has been added as aggregate, the resilient modulus is greater than in the reference mixture. For the bituminous mixtures in which an aggregate saturated in salt water has been used for its manufacture, the results of the resilient modulus test, dynamic modulus test, and fatigue life test are lower than in the reference mixture, especially when the specimens are submerged.

Repeatability and Reproducibility Analysis for Functional Test Results from Asphalt Mixture Performance Tester Cyclic Fatigue Test

“…As shown by the integral in Equation 9, v norm encompasses the total area between individual C versus S curves and the curve that resulted from optimization of all individual curves with normalization based on the number of curves considered and a scaling factor, k . The multiplier k was applied to change the magnitude of v norm from approximately 10 −5 to 1 for convenience. The calculation of v norm for repeatability and reproducibility is detailed in the following sections.…”

“…Researchers have taken various methods to handle the variation of test results used to calibrate functional relationships. For dynamic modulus data, a common practice is to consider measured results for each temperature and frequency combination and analyze the variation independently even though the data are typically used to create a mastercurve model (3)(4)(5). Bonaquist conducted the repeatability and reproducibility analysis for each combination of temperature and frequency following the ASTM standards (6).…”

The Impact of Water and Road Salt with Anti-Caking Agent on the Stiffness of Select Mixes Used for the Road Surface

“…In 2020, a key work by Gandara et al [ 20 ] was published, in which the authors focused on the influence of road salt on the properties and parameters of 3 types of bituminous mix combinations (PA 16—porous asphalt on 50/70 ordinary asphalt and AC16 asphalt concrete): immersed in a salt solution, as an additive to aggregate and aggregate additive and soaking in salt. Various salt concentrations of 3.5%, 5%, and 10% were taken into account, the soaking time was 3 days, and the test temperature was 20 °C.…”

Laboratory Evaluation of Mechanical Properties of Asphalt Mixtures Exposed to Sodium Chloride

“…The dynamic modulus |E*| defines the viscoelastic behavior of asphalt mixtures for a spectrum of temperatures and loading frequencies ( 21 ); furthermore, it is a typical input for mechanistic–empirical pavement design ( 22 ). Compared with dynamic modulus, the resilient modulus is experimentally evaluated by applying a rest period in the testing procedure ( 23 ), as this is assumed to mimic real traffic loading better ( 24 ). The indirect tension (IDT) mode is a testing method for assessing both the dynamic modulus and the resilient modulus ( 25 ).…”