Discussion. Research and Its Application to Road Construction.

Abstract

observed that it was rarely possible to isolate the contributions of the practising highway engineer and the research worker; they merged into one result. That was as it should be, for it was very easy inside the laboratory to be led away from practical needs. The research worker who found a fascinating new form of test or who made a new discovery might be tempted, in pressing its claims, to turn a blind eye to the difficulties of engineers. On the other hand, the engineer might try to play safe by turning a blind eye to the potentialities of a new line of thought. D r Glanville had always tried to bring the two together, because the combination was a healthy one.102. On the question of pavement design, Dr Glanville said that the difficulties seemed to multiply with experience rather than diminish. He said "seemed to" because he did not believe that they really did; it was merely that an attempt was being made to bring more scientific precision into the use of natural materials, which were very variable in quality and had to be used in Britain under conditions that might change from day to day and even from hour to hour. It was necessary to know a great deal more about these uncertainties and variabilities, and to find means of dealing with the practical difficulties. Methods of design must be resolved into practical rules which could be applied with reasonable hope of success.103. Dr Glanville recalled that before the 193945 war an eminent engineer had said that the roads which were being built were only the foundations of the roads of the future. That was certainly true. Recently, when a length of by-pass road had been opened up and a new section put down it had been necessary to dig through three concrete roads in succession. It was interesting to find that the present answer in Germany, as those who had heard Dr Georner's address a week ago on German motor roads would realize, seemed to be to build three roads on top of one another at the beginning. In that address the great thicknesses of construction used at the present time in Germany had been emphasized. Apparently the Germans did not worry about cost; British engineers had not got so far as that. However, although the Germans were doing so much work they did not use methods of pavement design comparable to those which were being developed in Britain. Some good method of design was urgently needed, and more must be known about the reserve of strength; it would then be possible to build a known reserve of strength into the new roads.104. Dr Glanville asked if the Authors would give further information concerning t