Determination of master curves for asphalt mixtures by means of IT-CY tests
The concept of ecologically conscious and energy saving roads must be expanded to the performance of the asphalt mixtures as well as to the test related to it. This paper investigates the tests focusing on a better description of the behaviour of asphalts as well as on a deeper revelation of the impact of different compositions. Based on the international experiences the recording of the asphalt´s complex module over the entire temperature range by the determination and evaluation of the mater-curves appeared as a possible solution for more precise description of the asphalt behaviour.
Calculation of the equivalent temperature of pavement structures
Due to the difficulties of the description of temperature variation, rating of asphalt pavement structures respecting fatigue is made on equivalent temperature. In general, equivalent temperature is calculated according to average and weighted air temperature. It is proven, based on processing numerous data provided by the temperature detectors laid in the pavement structures as well as determination of the partial fatigue values, which the present method used to calculate the equivalent temperature results in data losses. Furthermore, it is proven, that pavement structure temperature based on air temperature can be determined only to limited extent. Knowledge of temperature distribution of the pavement structure provides the possibility of more accurate design.
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.