Razvoj modela za faktore korekcije ugiba fleksibilnih kolovoznih konstrukcija s obzirom na temperaturu

Abstract

Temperatura asfaltnih slojeva ima, pored opterećenja, najznačajniji uticaj na veličinu ugiba ispod samog opterećenja ili blisko opterećenju. Postojeći modeli za faktore korekcije razvijeni su na bazi inostranih iskustava i ne održavaju u potpunosti asfaltne mešavine koje se primenjuju u regionu. U radu je prikazano istraživanje sa ciljem da se razviju modeli za faktore korekcije koji se mogu primeniti u postupcima analize ugiba i proračuna nosivosti postojećih kolovoznih konstrukcija. Istraživanje se sastoji iz tri dela. Moduli asfaltnih mešavina AB11s za habajući sloj i BNS 22sA za gornji noseći sloj dobijeni su na osnovu master krivih za ove mešavine koje su konstruisane na bazi laboratorijskih ispitivanja modula krutosti. Proračun ugiba vršen je programom EVERSTRESS za tri nivoa fleksibilnih i polukrutih kolovoznih konstrukcija, sa debljinama asfaltnih slojeva od 100 mm do 210 mm. Dobijeni ugibi poslužili su za proračun faktora korekcije na referentnu temperaturu od 20oC za raspon temperatura od 10oC do 30oC koji se smatra realnim i poželjnim za merenje ugiba fleksibilnih kolovoznih konstrukcija. Konačno, model za faktore korekcije razvijen je i validiran primenom neuronskih mreža. Model obuhvata fleksibilne i polukrute kolovozne konstrukcije, i pored temperature asfaltnih slojeva uključuje i debljinu slojeva i rastojanje ugibomera od centra opterećenja.

The temperature of asphalt layers have, in addition to loading, the most significant influence on the pavement deflections below the load and within the deflection bowl. Existing models for temperature correction factors have been developed on the basis of foreign experience and do not take into account the asphalt mixtures used in the region. The paper presents a research with the aim of developing models for correction factors that can be applied in the procedures of deflection analysis and bearing capacity calculation of existing pavement structures. The research consists of three parts. The stiffness moduli of asphalt mixtures AC11s for the wearing course and AC 22sA for the base layer were obtained from their master curves, which were constructed on the basis of laboratory tests of stiffness modules. The calculation of deflection was performed by the EVERSTRESS program for three levels of flexible and semi-rigid pavement structures, with asphalt layer thicknesses from 100 mm to 210 mm. The obtained deflections were used for the calculation of the correction factor to the reference temperature of 20oC for the temperature range from 10oC to 30oC, which is considered realistic and desirable for deflection measurements on flexible pavement structures. Finally, a model for correction factors was developed and validated using neural networks. The model includes flexible and semi-rigid pavement structures, and in addition to the temperature of the asphalt layers, it also includes the thickness of the layers and the distance of the deflecton from the center of the loading.