Final Report Summary - GREEN CONCRETE (Development of gravel turf consisting of recycled construction materials as an economical and ecological method for permeable and surface consolidation ...)
The GREEN CONCRETE project has been set up by a German-Italian-Austrian consortium. The aim was to acquire comprehensive information of gravel turf and, in case of positive outcome, market the technology. The scientific basis for the project was the existing knowledge about gravel turf consisting of natural gravel. The investigation plan of the GREEN CONCRETE project went beyond the state of the art since:
- For the first time ever construction recycling material has been tested on its suitability for gravel turf.
- For the first time ever a comprehensive investigation program has been carried out, including all necessary and partially interacting properties of gravel turf in one project and hence providing comparable data.
- For the first time a grasses and herbs seeds assortment has been tested and optimized in course of the project.
Gravel turf is an ecological and economical technology for surface consolidation, particularly suitable for parking areas. The vegetation base layer of gravel turf consists of recycling materials or natural gravel in combination with a certain allotment of soil and / or compost. The components have to be mixed according to a certain grain size distribution. On this base layer suitable grasses and herbs are planted. The green appearance of gravel turf is certainly a visual improvement of the otherwise grey cityscape. Furthermore, the plant's evapo-transpiration has positive effects on the urban microclimate.
The decisive properties of gravel turf are:
- recycling of construction materials instead of costly depositing;
- cost effective and easy construction;
- release of sewage system (no canals, oil separators, drainage systems needed);
- contribution to passive flood prevention.
Ecological benefits of gravel turf are:
- high biodiversity;
- interlinking of habitats (function of 'Tritt-Stein-Biotop');
- on site seepage of precipitation;
- renewal of groundwater;
- improvement of the microclimate through plant evaporation;
- pollutant decomposition or absorption;
- usage of recycling materials is resource saving.
The main phase of the project focused on the acquisition of comprehensive data of the physical, chemical, construction- and vegetation-technical properties of the test materials: load bearing capacity; water permeability; soil density; evenness; environmental compatibility; water balance; plant development. The emphasis of the final phase was laid on the survey of all test results and the drawing up of a recommendation of the best suitable materials and construction methods for each SME partner.
The Landesanstalt fuer Weinbau und Gartenbau in Veitshoechheim and the Fachhochschule Erfurt examined the construction technical and geotechnical properties: chemical properties (pH-value etc.); physical properties (electric conductivity etc.); resistance against frost dew alternation and in situ crushing and the environmental compatability (pollutants etc.). The University of Natural Ressources and Applied Life Sciences checked the plantability by means of an adapted 'Kresse-Test'. Finally, 13 materials have been nominated for the construction the test sites.
The main phase started with the construction of the test sites at four locations. Throughout the whole project the scientific team laid emphasis on the comparability of research results at the all test locations. Hence, a criteria catalogue has been drawn up including all construction steps from plane properties to greening and maintenance. In preparation of the field investigations, the scientists developed a comprehensive investigation program. Two test categories were distinguished. The basic tests focus on the documentation of the geotechnical properties of the material variants and the development of the plant cover. The three special tests covered additional important issues of gravel turf concerning its applicability.
The construction technical and geotechnical investigations included: load bearing capacity; water permeability; soil density; evenness of surface.
The following vegetation technical aspects have been documented: total plant cover; grasses and herbs proportion; vitality; flowering aspect; average plant height.
The test sites have been planted with two different seed assortments. One, consisting solely of grass seeds, was based on the suggestions of the Forschungsgesellschaft Landschaftsentwicklung und Landschaftsbau e.V.. The second seed assortment has been composed using grasses and herbs. The aim of the planting is to establish a homogeneous sustainable plant cover. To optimise the functionality it was necessary to monitor the development of every single species. To perform the vegetation observation developed an adapted point line method.
The GREEN CONCRETE project proved that gravel turf is a mature method to consolidate parking areas and low frequented public thoroughfare. All recommended material variants fulfilled the geotechnical requirements. The tested recycled construction materials are fully environmental compatible. The content of harmful substances, if actually found in the seepage water, did not exceed the national limits. Thanks to quality standards and assurance in the participating states, it may be assumed that the use of recycled construction materials is uncritical in terms of environmental aspects. Almost one hundred percent of the precipitation drained away on site and enriched the groundwater or has been stored in the vegetation base layer, facilitating plant growth and evaporation. Both, recycling construction materials and natural gravel, are suitable for the construction of vegetation base layers. The recycling construction materials revealed even better results concerning the plant development. Based on the results of the vegetation observations the functionality, ecological value and economical aspects of the GREEN CONCRETE seed assortment have been optimised. The very positive results of the GREEN CONCRETE project and the economical and ecological benefits of gravel turf in comparison to other surface consolidation methods argue distinctively for increased application of gravel turf.
Thanks to the GREEN CONCRETE project the SME partners possess the knowledge to produce suitable materials for gravel turf and construct it. Since presence of the project results the SMEs included gravel turf in their range of products and market it actively. The GREEN CONCRETE project filled a knowledge gap in the research area of gravel turf. For the first time ever the suitability of recycling materials for the construction of gravel turf has been tested. All, partially interacting, aspects have been reviewed comprehensively.
- For the first time ever construction recycling material has been tested on its suitability for gravel turf.
- For the first time ever a comprehensive investigation program has been carried out, including all necessary and partially interacting properties of gravel turf in one project and hence providing comparable data.
- For the first time a grasses and herbs seeds assortment has been tested and optimized in course of the project.
Gravel turf is an ecological and economical technology for surface consolidation, particularly suitable for parking areas. The vegetation base layer of gravel turf consists of recycling materials or natural gravel in combination with a certain allotment of soil and / or compost. The components have to be mixed according to a certain grain size distribution. On this base layer suitable grasses and herbs are planted. The green appearance of gravel turf is certainly a visual improvement of the otherwise grey cityscape. Furthermore, the plant's evapo-transpiration has positive effects on the urban microclimate.
The decisive properties of gravel turf are:
- recycling of construction materials instead of costly depositing;
- cost effective and easy construction;
- release of sewage system (no canals, oil separators, drainage systems needed);
- contribution to passive flood prevention.
Ecological benefits of gravel turf are:
- high biodiversity;
- interlinking of habitats (function of 'Tritt-Stein-Biotop');
- on site seepage of precipitation;
- renewal of groundwater;
- improvement of the microclimate through plant evaporation;
- pollutant decomposition or absorption;
- usage of recycling materials is resource saving.
The main phase of the project focused on the acquisition of comprehensive data of the physical, chemical, construction- and vegetation-technical properties of the test materials: load bearing capacity; water permeability; soil density; evenness; environmental compatibility; water balance; plant development. The emphasis of the final phase was laid on the survey of all test results and the drawing up of a recommendation of the best suitable materials and construction methods for each SME partner.
The Landesanstalt fuer Weinbau und Gartenbau in Veitshoechheim and the Fachhochschule Erfurt examined the construction technical and geotechnical properties: chemical properties (pH-value etc.); physical properties (electric conductivity etc.); resistance against frost dew alternation and in situ crushing and the environmental compatability (pollutants etc.). The University of Natural Ressources and Applied Life Sciences checked the plantability by means of an adapted 'Kresse-Test'. Finally, 13 materials have been nominated for the construction the test sites.
The main phase started with the construction of the test sites at four locations. Throughout the whole project the scientific team laid emphasis on the comparability of research results at the all test locations. Hence, a criteria catalogue has been drawn up including all construction steps from plane properties to greening and maintenance. In preparation of the field investigations, the scientists developed a comprehensive investigation program. Two test categories were distinguished. The basic tests focus on the documentation of the geotechnical properties of the material variants and the development of the plant cover. The three special tests covered additional important issues of gravel turf concerning its applicability.
The construction technical and geotechnical investigations included: load bearing capacity; water permeability; soil density; evenness of surface.
The following vegetation technical aspects have been documented: total plant cover; grasses and herbs proportion; vitality; flowering aspect; average plant height.
The test sites have been planted with two different seed assortments. One, consisting solely of grass seeds, was based on the suggestions of the Forschungsgesellschaft Landschaftsentwicklung und Landschaftsbau e.V.. The second seed assortment has been composed using grasses and herbs. The aim of the planting is to establish a homogeneous sustainable plant cover. To optimise the functionality it was necessary to monitor the development of every single species. To perform the vegetation observation developed an adapted point line method.
The GREEN CONCRETE project proved that gravel turf is a mature method to consolidate parking areas and low frequented public thoroughfare. All recommended material variants fulfilled the geotechnical requirements. The tested recycled construction materials are fully environmental compatible. The content of harmful substances, if actually found in the seepage water, did not exceed the national limits. Thanks to quality standards and assurance in the participating states, it may be assumed that the use of recycled construction materials is uncritical in terms of environmental aspects. Almost one hundred percent of the precipitation drained away on site and enriched the groundwater or has been stored in the vegetation base layer, facilitating plant growth and evaporation. Both, recycling construction materials and natural gravel, are suitable for the construction of vegetation base layers. The recycling construction materials revealed even better results concerning the plant development. Based on the results of the vegetation observations the functionality, ecological value and economical aspects of the GREEN CONCRETE seed assortment have been optimised. The very positive results of the GREEN CONCRETE project and the economical and ecological benefits of gravel turf in comparison to other surface consolidation methods argue distinctively for increased application of gravel turf.
Thanks to the GREEN CONCRETE project the SME partners possess the knowledge to produce suitable materials for gravel turf and construct it. Since presence of the project results the SMEs included gravel turf in their range of products and market it actively. The GREEN CONCRETE project filled a knowledge gap in the research area of gravel turf. For the first time ever the suitability of recycling materials for the construction of gravel turf has been tested. All, partially interacting, aspects have been reviewed comprehensively.