Analyses of the Influence of Material Characteristics on Pavement Design

Abstract

Currently, only empirical design methods are used in the application of well-known standards for pavement structure design. Given this fact, it is assumed that material characteristics correspond to average quality materials. Thus, the aim of this study included examining the influence of material characteristics on pavement design analyzing changes in the cement bound base layer (CBL) characteristics with respect to the occurrence of cracks and changes in the asphalt layer given typical seasonal changes. The study involved varying CBL modulus as 15 GPa, 10 GPa, and 5 GPa. Additionally, the moduli of asphalt layers were varied from 6 MPa to 2 MPa to simulate real conditions in pavement structure life. The analyses indicated that there was a significant difference in pavement behavior with respect to changes in material characteristics. Given these significant differences, it is extremely important to properly define material characteristics while using empirical design methods. Proper material characterization combined with the utilization of empirical and analytical methods increases the possibility of reducing layers thickness to design cost-effective structures.Keywords: pavement structure; stress; strain; displacement; design methods ANALIZA UTJECAJA KARAKTERISTIKA MATERIJALA NA DIMENZIONIRANJE KOLNIČKE KONSTRUKCIJE Sažetak: Prilikom dimenzioniranja kolničke konstrukcije, u suvremenoj se praksi primjenjuju poznati standardi unutar empirijskih metoda dimenzioniranja. Pritom se svojstva materijala pretpostavljaju s obzirom na prosječnu kvalitetu standardnih cestograđevnih materijala, bez dodatne analize eventualnih promjena tijekom vremena i zbog naprezanja. Svrha ovoga rada je istražiti utjecaj svojstava materijala na projektiranje kolničke konstrukcije kroz analizu utjecaja promjena karakteristika cementom stabiliziranih nosivih slojeva (CSS/CBL) nakon pojave pukotina u sloju i kroz analizu utjecaja promjena u ponašanju asfaltnih slojeva tijekom uobičajenih izmjena godišnjih doba. Za potrebe analize mijenjane su vrijednosti modula elastičnosti cementom stabiliziranih slojeva (CSS/CBL) i asfaltnih slojeva kako bi se simulirali stvarni uvjeti tijekom projektnog razdoblja. Analize su pokazale da postoji značajna razlika u ponašanju kolničke konstrukcije pri promjeni svojstava materijala. Zbog toga je bitno pravilno definirati karakteristike materijala prilikom korištenja empirijskih metoda projektiranja. Uz pravilnu karakterizaciju materijala i usporedno korištenje empirijskih i analitičkih metoda, postoji mogućnost smanjenja debljina pojedinih slojeva kolničke konstrukcije u svrhu dobivanja racionalnije konstrukcije Ključne

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