The construction of gravel turf is comparatively simple. In case of suitable subsoil the construction of a 30 cm of vegetation base layer is sufficient. This is called “one layer method”, as the whole layer consists of the same material.
If the subsoil is unsuitable or heavy loading intensity is expected, the subsoil has to be exchanged and a plane constructed. Suitable materials for the plane are natural gravel as well as recycling materials, as they are commonly used for road constructions.
The plane of gravel turf should have the following parameters
Vegetation base layer
The vegetation base layer should correspond to the following criteria:
The seeds are sowed by hand with 10 g seeds per m². The vegetation base layer has to be watered before and after the sowing to ensure optimal contact between seeds and substrate.
In the course of the GREEN CONCRETE project two different seeds assortments are tested. One assortment is based on the recommendation of the FLL (RSM 5.1, FLL 2008) and consists solely of grasses seeds. The second assortment has been developed by the University of Natural Resources and Applied Life Sciences Vienna. This seeds mixture is composed of grasses and herbs, which are suitable for all project research locations.
At least 50% of the gravel turf surface needs to be covered by plants in order to be acceptable. Thus growth maintenance is obligatory. It is recommended to prevent any usage of gravel turf for 3 month and regularly irrigation. In case of pour nutrient supply the donation of fertiliser may be necessary.
The degree of maintenance effort of gravel turf depends predominantly on the intensity of usage. The mowing frequency for instance depends on the stress the plants have. It is assumed, that the test sites of the GREEN CONCRETE project with defined loading (2 loadings per week) have to be mowed 3 times per year.
The removal of fallen leaves and waste may also be necessary.
If snow clearence is necessary, it should be conducted with a snow plough. The shield of the snow plough shall be kept 3 to 5 cm above surface to avoid damage of the plant cover. Commonly used road grit may be dispersed.