The principal criteria applicable to the mix design and the properties of lean concrete are: - splitting tensile strength in the region of 1.7 MFa and compressive strength in the region of 15 MPa at 28 days; - good erosion resistance; - lowest possible modulus of deformation; - possibility of...
Mix design and properties of lean concrete for sub-bases
A continuously reinforced concrete pavement (0.35 m thick) for the steel mill Sidmar in Belgium
The project consists of the construction of a continuously reinforced steel slag concrete pavement (0.35 m thick) on a base course of slag sand-bound granular material (0.85 m thick). The road (area 8,000 m2, width 10 and 17 m) has to lenable the transportation of hot (800 0 C) steel...
Critical assessment of various construction techniques
The long-term behaviour of various types of road pavement construction can be estimated or prognosticated from a methodical assessment of the condition of the roads and the associated data collection. Prognoses can be made not only with regard to technical cri teria, but also with regard to overall cost trends...
Results of measurements on concrete roads
Besides theoretical work, investigations on specimens in the l~boratory and practical tests, in-situ measurements provide the means of assessing and further developing new concrete pavement systems. It emerges that, apart from the behaviour of a c?nc7e~e pavement at an early age (random cracking), s~gn4flcant changes (e.g., sinking, opening of joints....
Effect of cement-bound sub-bases on cracking
Cement-bound sub-bases (CaSBs) are constructed ~ithout joints. During and after hardening, cracks may be formed in consequence of drying and/or cooling, even if the sub-base has noc yet been subjected co any traffic load. It would be desirable to have no cracks or only very fine ones (capable of eransmieting...
Construction of airfield pavements with concrete
Concrete pavements have for years been successfully used in airfield construction. The relatively high weight of the landing gear of large aircraft requires pavement thicknesses which are considerably higher than those of concrete roads. The construction of airfield concréte pavements requires appropriate placing techniques. On account of the high loads...
Recommendation for the maintenance of concrete roads in the Federal Republic of Germany
The "Code of practice for the maintenance of concrete roads" ("Merkblatt für die Erhaltung von Betonstrassen") was published in the Federal Republic of Germany in 1985. It is based on the 1968 edition, but clearly reflects further developments in maintenance techniques, e. g., improved drainage. The code forms part of...
Connecting devices between concrete road pavements and existing highway structures
Civil engineering structures, such as bridges, flyovers and underbridges, are discontinuities in a concrete road. Usually, the concrete pavement has to be cut across and in those cases, such as small underbridges, where the concrete pavement can be laid without any discontinuity, differential settlements between embankment and structure have to...
Side drainage and sub-soil drainage layer operation and performance
A very favourable result emerges from the assessment of the soundness of structural arrangements adopted and developed over the past ten years (3rd International Conference at Purdue, April (985). After briefly reviewing this positive achievement resulting from closely concerted action of road managers, practical engineers and researchers, the authors more...
Spanish realizations of steel fiber pavements
The development of the steel fiber reinforced concrete pavements has experienced a big apogee in Spain in the last three years. The object of this work is to display the most important realizations made in the field of roads. harbours, airports, etc., analyzing their characteristics and behaviour. ROADS - Base...
Economic appraisal of cement concrete versus asphaltic concrete pavements
1. Introduction Since 1962 no cement concrete had been used in the governmental road sy~tem as a paving material. After 1975 the need to use this material again was felt more and more. Somewhere about 1982, during the decision making period regardi~g the type of pavement to be chosen for...
Structural design of concrete pavements
Under present economic conditions the use of bitumen is being reduced as much as possible. For more than twenty years the application of semi-rigid pavements has revealed the drawbacks but also the advantages of such structures. The chief advantage is their low cost, which can be further reduced if the...