Paper by NAGEL from ISCR 5th 1986 Aachen Germany
The construction of concrete pavements is associated with various requirements to be fulfilled, e.g.: full-width construction stripwise construction, but extending over the full width ) e.g., construction of new cancrete roads addition of traffic lanes to existing carriageways ) e.g., on roads in use by traffic renewal of traffic lanes and individual slabs ) e.g., on roads in use by traffic construction of parking areas and hardstandings ) e.g., for military purposes paved areas for special purposes )e.g., in the chemical industry These various requirements necessitate specific adaptation of the chosen plant to the work to be carried out. They also call for proper adjustment of the concrete technology, taking particular account of the aggreRates and the suitability of the cement employed. Slipforming offers an undeniably economical method of construction in this context. It does, however, require a high level of skill and competence on the part of those involved. Any defects of construction occurring during tbe concreting process can, if at all, subsequently be corrected only at considerable'expense and effort,i.e., the construction procedure must be so reliably controlled that such defects will not occur at all. Conventional concreting (between fixed forms) can be rated as a "safe" method, in which the construction materials can be used in the favourable borderline range, which has a beneficial effect on the qualitative result. In connection with the particular purpose for wbich the pavement is intended, questions of evenness transversely to the direction of concreting, for example, may be of major importance. It is certainly not good enough to "sanction" inadequate performance by compensating for this through deduceions from the price paid to the contractor if the defects in question had been avoidable by using suitable construction methods. The "employer's risk" that this involves does. however. mean that the competent employer or client must have a say in choosing what construction method to use, in connection with which the problems of economy and attainable quality of the finished work will have to be carefully considered.