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In this paper, we studied the properties of hot mix asphalt with substituted waste glass, used for surface layers, made in accordance with standard EN 13108-1. The waste glass was sourced by overcrushing glass from old bottles and broken glass from window frames. We aimed to substitute fractions of individual and cumulative aggregate and fillers in the mineral mixture with glass. We also studied how the compaction in the Marshall's tamper affected the overcrushing of the mineral mixture with the waste glass. Increasing the glass fraction in the asphalt mixture decreased the density, stability, and void content of the mixture, as well as the proportion of voids filled with bitumen.

Today, the road construction profession is more than ever facing limited and increasingly expensive resources for component materials of asphalt mixtures, which has also led to the need for continuous research on the use of waste materials. One such potentially usable waste material is ash obtained by the combustion of wood biomass that is used to produce heat and electricity. The goal of this paper is to ascertain the possibility of using wood ash (WA) as the filler in asphalt concrete mixtures for the base-wearing layers of a pavement. The properties of Marshall stability (MS), quotient (MQ) and deformations, and the indirect tensile strength of water-conditioned samples and dry samples were tested on asphalt samples of an AC16 surf mixture with different contents of wood ash as the filler. The obtained values of MS and MQ indicate that a 50% content of bio ash in the filler results in an increase in asphalt’s resistance to the appearance of plastic deformations and greater tensile strength and in good asphalt resistance to the action of water.

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In this study, we evaluated the elastic and mechanical properties of a new type of cement-stabilised material made with steel slag, varying the content of cement and steel slag. To study the elastic properties of these mixes, we measured their density, compressive strength and ultrasound pulse velocity at curing ages of 7, 28 and 90 days. The aggregate type and curing age greatly affected the elastic properties and varied much depending on the cement content. The Poisson's ratio chosen in analyses had little influence on the dynamic modulus. Various expressions given by building codes were used to predict the elastic properties of the mixtures. These codes generated very different values of the static modulus of elasticity, making most of them unsuitable for predicting the elastic properties of cement-stabilised materials. Using our experimental data, we provide the best combination of existing equations to predict elastic properties, and we conclude that measuring the ultrasound pulse velocity is a suitable way to predict the mechanic and elastic properties of cement-stabilised materials.

The era of intensive construction of new roads in Croatia is behind us. Today road agencies are focused on maintaining and preserving existing roads. Selection of an appropriate maintenance strategy is a complex task, which includes factors such as the current condition of the pavement, road classification, traffic volume etc. These factors are usually implemented in pavement management systems. The key components of pavement management systems are pavement performance prediction models such as artificial neural networks. This paper analyses the possibility of using artificial neural networks to evaluate existing pavement condition, and its possible application for defining the maintenance strategy of national roads. A backpropagation neural network was applied on 481.3 km of national roads in the Osijek-Baranja County. The obtained results indicated that artificial neural networks could be used for optimization of maintenance or rehabilitation strategies, and for the assessment of pavement condition at the project and network level.

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