Environmental load for design of airport concrete pavements

Abstract

This paper presents a method for calculating the environmental load that is essential to the mechanistic design of airport concrete pavements, based on the equivalent linear temperature difference (ELTD) between the top and bottom of the slab. To assess its application, the total ELTDs at 17 airports (military and civilian) across the Korean peninsula, representing the full range of regional climates in the country, were calculated according to slab thickness.Based on the results, a multiple regression model was developed. The environmental load can be considered by simply inputting the ambient temperature, relative humidity and slab thickness into the proposed models. The results can be applied worldwide.Notation h slab thickness (mm) T large largest monthly average daily temperature change (8C) T temperature difference between a specific depth and the bottom of the slab (8C) T eq equivalent linear temperature difference (ELTD) between top and bottom of the slab (8C) T sh differential shrinkage ELTD (8C) T sh-re differential shrinkage ELTD considering stress relaxation (8C) T total total ELTD (8C) t age of concrete (d) RH relative humidity RH low lowest monthly average RH (%) V =S volume to surface area ratio of the slab (mm) exposed to ambient air z distance to a specific depth from mid-depth of the slab (mm) a regression coefficient AE c coefficient of thermal expansion of concrete (8C À1 ) å sh drying shrinkage of concrete å ush ultimate drying shrinkage of concrete Ö rate of stress relaxation

Pavement Condition Index Model for Mechanistic–Empirical Design of Airport Concrete Pavements Considering Environmental Effects

“…For the environmental loads, an ELTD ranging between −30 and 0 • C was used to consider shrinkage and creep, in addition to the temperature of the concrete pavement [21]. ELTD is the temperature difference between the top and bottom of a slab for which the actual nonlinear vertical temperature distribution can be converted into a mechanistically equivalent linear distribution [22].…”

“…The nonlinear vertical shrinkage and creep distributions can be added after converting them into mechanistically equivalent linear temperature distributions. The ELTD of the target airports was calculated using the multilinear regression model expressed by Equation (3) [21]:…”

Behavior of Airport Concrete Pavement Slabs Exposed to Environmental Loadings

“…In addition, the top of the slab dries faster than the bottom, resulting in differential drying shrinkage because the slab surface is in direct contact with the ambient air [4][5][6]. Therefore, slab curling occurs, wherein the slab bends upward or downward owing to the difference in contraction and expansion between the top and bottom of the slab [3,[7][8][9].…”

Editorial

“…The paper includes a case study of a recent runway resurfacing project at Manchester Airport where the material was used. The paper by Park et al (2015) presents a method for calculating the environmental load of airport concrete pavements. Current multi-layer elastic analysis designs do not take into account this load and the paper explains the analysis used to develop a multiple regression model that can be applied worldwide.…”