A 7 Lu 8% reduction in compactness of air-entrained concrete with respect to the maximum one is a positive factor from the frost, -salt resistance standpoint, nevertheless, such compactness of roller compacted concrete can lead to dangerous results. The existing methods of controlling the compaction rate (measuring the volume of...
Stresses Analysis of Cemented Bases on Concrete Pavement
Traditional methods for road concrete pavements design do not take into account the structural contribuition of cemented bases and its fatigue consumption uiidei the traffic loads. Sections designed without major care about the structural reponses of those bases can develop early cracks, decreasing the structural capacity of the pavement. This...
FEM Analysis on the Dynamic Behaviour of Concrete Road Superstructures
As a general rule procedures for the sizing of road superstructures only refer to static stress. Possible dynamic effects induced by loads are introduced by amplifying their intensity or by considering the dynamic modulus of the materials. Under variable stress in time, the real behaviour of a superstructure is remarkably...
Possibilities of Quality Determination of Concrete Surface Layers
Possibilities of applying methods of surface absorption, mercury intrusion porosimetry, pull-off strength tests and thermal analysis in the assessment of the state of the surface layer of a concrete airport runway are given. The results of the tests of properties of differently deteriorated surface layers of concrete in an airport...
New Opinions in the Friction Problematic with Brushed Textures and Exposed Aggregates
Washed or fine brushed concrete was introduced in the Netherlands, replacing rough brushed concrete, to reduce the road noice. In many cases the minimum friction coefficient required was not reached. However, measurements carried out some months later showed an improvement of the results. To investigate if this improvement of the...
Surface Characteristics and Driving Comfort on two Swedish Concrete Roads
In Sweden there is an increased interest in the performance based specifications of concrete roads, such as wearing resistance, friction and noice. Recently two concrete roads have been constructed with the special intention to improve the surface characteristics. Both roads were constructed with concrete that is resistant to wear and...
Skid Resistance of Exposed Aggrcgate Concrete
From 1990 to 1992 exposed aggregate concrete was used for the construction of 14 sections of Austrian motorways. This technology offers a noise reduction and a higher level of skid resistance. In order to evaluate the skid resistance of these surfaces in comparison to others, measurements were carried out in...
Measurement and lrnpruveiiieiit of Road Evenness on Concrete Roads
The evenness of concrete roads is one of the main concerns of this type of pavements in Spain. In the last years many improvements have been achieved in the way of finishing concrete roads. International Roughness Index (IRI) measurements are normally done to evaluate evenness. However, the normal approach used...
Noise Reducing Concrete Block Pavements
In recent years several investigations were carried out in Germany aimed at reducing the tyre-road noise on concrete block pavements. The results show that these pavements can be constructed with a surface producing the same low traffic noise level as the reference asphalt road surface. In the paper, conclusions are...
European Concrete Pavement Trial Project in the USA
The State of Michigan in the United States of America constructed a trial project that incorporated highway pavement design features from Germany and Austria. The project considered a 25.4 cm unreinforced concrete pavement, over a 15.2 cm lean concrete base, over a 40.6 cm granular frost layer. The concrete pavement...
Noice Reducing Exposed Aggregate Surfaces – Experience and Recommendations
In 1990 a technique for building pavements with a noice reducing concrete surface was developed in Austria. The top layer contains aggretate with 8 mm maximum size. The surface is sprayed with a retarder and brushed the next day to expose the aggregate. This technique has been used on 120...
Developments for the Exposed Aggregate Technique in Austria
For the time being the exposed aggregate technique is the cheapest way of building a rigid pavement with a surface that is noise reducing, skid resistant and durable. The technique requires the use of specially adapted payers, very good-natured retarders and a very efficient curing. Special combinations of surface retarders...