Materials

The use of CD 40-A cement eliminates the classical procedures of measuring plastifying and air entraining additives at the preparation on site of the road concrete. The article presents the main characteristics of CD 40-A and the results of laboratory tests carried out to establish the influence of this type...

From 1991 to 1993 60 km of carriageway were reconstructed on the motorway Salzburg-Vienna, re-using the old concrete pavement 100% on the work-site. The fine material (0/4) that resulted when crushing the old pavement was added to the old granular subbase which without would have been too coarse-grained to be...

Aggregates were obtained from an alkali-silica damaged concrete road slab aggregates and used for road base concrete with different kinds of cement (low alkali cement, high alkali cement). After analysing the samples produced with these mixes, which were exposed for up to one year to different hardening conditions, no alkali-silika...

Reconstruction of concrete pavements can be performed by fracturing the existing concrete slabs into small pieces in situ and then placing a leveling course and overlay. The fractured slabs provide a firm base for the new pavement. The technique is increasingly used for the reconstruction of concrete pavements where the...

The problem of using fine-grained (sand) concrete instead of the "classic one in the construction of road and airfield pavements is analysed. In sand concrete the coarse aggregate, crushed stone or gravel, are substituted by natural sand or a blend of natural sand and screenings 0.5 (10) mm. The use...

In the last few years the interest for preventive environment measures has increased. That is the reason for stimulating the re-use of waste materials as a means of recycling. With the aim of stimulating the recycling of waste materials, the interest in using cement to stabilize different materials increased. This...

Cement for concrete pavements has to meet special requirements. Besides cement properties which influence the fresh concrete, the cement is of great importance for the durability of concrete pavements. If the joints in the young concrete are not sawn early after paving, cracks can form in the pavement. With cracking-frame...

In Germany the use of concrete with aggregates obtained from crushed concrete (RC aggregate) has been quite limited in comparison to other countries such as the USA and Austria. This situation is caused mainly by the lack of appropriate regulations for this kind of application. For this reason, the award...

To give guidelines for the mix design on high performance concrete with high wear resistance, and to study wear of high strength concrete, the Norwegian cement producer NORCEM operates a test rig specially developed for this purpose. The tests show concrete to give 2-3 times the wear resistance of asphalt....

Two test sections were constructed with a base course of porous concrete under the emergency lane of a motorway. This base composed of new aggregates or recycled aggregates, has the strength of a cement treated base and the function both of bearing capacity and drainage. Mixed in Plant and placed...

Session Paper Indexes, Opening Addresses, General Reports, Oral Contributions and Closings from the 6th International Symposium on Concrete Roads 1990 Madrid Spain

In Spain the development of cement, specially for concrete pavements, has been based on making use of fly ash in cement production. Such a development was achieved after studying the characteristics of the available fly ash and the respective experiencies. The results led to a widespread use of this type...