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.
Thickness of the pavement structure layers represents an important data for the implementation into the database of roads already constructed, during the pavement strengthening design, particularly if the appraisal of the bearing capacity of the pavement structure is done by means of the Falling Weight Deflectometer, during reconstruction of pavements or during control of the newly constructed roads. If reconstruction is carried out by procedures of recycling of the existing pavement the details about the thickness of asphalt layers are important not only when determining the depth of the intervention but also when designing asphalt mixture. During quality control of the newly constructed road sections the Ground Penetrating Radar (GPR, georadar) can be used as the instrument for fast and efficient determination of the thickness of layers. Measuring is done at speeds that approx correspond to the speeds of traffic flow, so that disturbance of traffic is minimum, whereby the safety of participants in traffic and measuring personnel is increased. The paper presents several examples of determining the thickness of layers of road pavement structures by the non-destructive GPR method. The obtained results were compared to conventional methods of determining thicknesses that are used in Croatia, i.e. coring or data obtained by surveying methods during construction of the pavement structural layers. Measurements were done on completely new and existing roads of different age having the asphalt pavement.
A B S T R A C T R I~ S U M i ~The paper presents the results of a scientific research program focused on determining the effect of the fine particles content in granular stone materials on particular properties of the unstabilized base course. Grain-size distribution of a granular system was within the defined limits, and the percentage of fine particles (< 0.02 mm in diameter) ranged from 0 to 10% by mass. Two types of fine particles were tested, those of stone and clay origin. The specimens were compacted using five energy levels. Used lab. equipment was in compliance with the requirements of German (DIN) and Swiss (SNV) standards.The following characteristics were tested: -bearing capacity (CBR test) at optimum moisture content and after one freezing/thawing cycle -permeability (coefficient of permeability k).The obtained results were statistically analyzed and graphically presented. The most important outputs are:(a) Bearing capacity -within the research limits of 0 to 10% by mass, fine stone particles have positive effect and the bearing capacity increases, -fine clay particles content not higher than 5% by mass is acceptable; for higher percentages, the bearing capacity decreases.(b) Permeability -for fine stone particles content below 5% by mass permeability is still satisfactory; however, even a very small percentage of fine clay particles has an adverse impact on permeability.The conclusions are related to the tested materials and should be used as starting point for further investigation. Get article pre'sente les r&ultats d'un programme de recherche scientifique dont l'objet a cons#td a ddterminer l'influence des fines dam un mat&iau gmnuld sur certaines propridt& de la couche portante non li&. La granulomdtrie des mat&iaux a dt8 fix& dam les limites prescrites et la part destines (d'un diam&tre de 0,02 mm) a varid entre 0 et 10% en masse. Deux esp&es de fines ont dtd examin&s : le filler et l' argile. Les Ochantillons ont dt8 compact& en cinq degr&. Les appareils utih'se's dam les essais en laboratoire sont conformes aux normes allemandes (DIN) et suisses ($NV).Les propri&& suivantes ont ~t~ {tudi&s :
The influence of the calendaring process of nonwoven geotextiles on the water permeability normal to their planes, including influence of different loads, as well as pore characteristics investigated by two different methods has been studied. Methods of pore characteristics differ in obtaining different pore parameters. Two groups of samples were produced whereas first group is bonded by needle punching, while second group is needle punched samples taken from first group and additionally bonded by calendaring. Mass per unit area for both groups is in range of 150 to 500 g/m2, with increasing by 50 g/m2 for the next sample within groups. Calendaring process decrease water permeability of geotextile, but also decreases interval of geotextile water permeability change due to the applied pressure. Calendared geotextiles have controlled and predictable compressibility, respectively structure which will not significantly change in the practical application.
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