| 摘要 |
With sound absorption constructions for ballast-less track superstructures, which consist mainly of reverberant concrete plates, it is to be brought about that the sound levels in the region of such superstructures do not lie higher than in the case of conventional ballast superstructures. Investigations with rock wool mats, which were fastened expensively with wire netting, and with poured mineral grains, which were bonded with plastic, revealed that with these constructions only limited reductions, and in particular only in quite definite frequency ranges, can be achieved. With the structure according to the invention made of underlying mineral or rock wool plate and a layer of mineral grains arranged thereon which at the same time serves as ballast for the mineral material plates, a sound absorption is achieved, which is uniformly good over the entire frequency range, the mineral material plates covering the high and the mineral grains the low frequencies.
|
