| Summary: |
The reduction of non-renewable natural resources exploration has been a constant concern relating to the preservation of the environment that, simultaneously, encourages the use of alternative materials. Thus, over the last years the environmental sustainability has been demanding a progressive increase in the waste valorization in construction. This research project deals with a new application of the Recycled Construction and Demolition Waste as backfill material for geosynthetic reinforced structures (embankments with steep slopes and retaining walls).
The Portuguese Technical Committee on Waste Valorization in Geotechnical Works (CT-VROG) identified recently a group of wastes with valorization possibility in geotechnical works, among which are: steel slag; tyre wastes; construction and demolition wastes and bottom ash from municipal solid waste incineration.
Although the different types of wastes identified by the CT-VROG are in distinct research stages related to the possibility of valorization in geotechnical works, either from national or international point of view, those which are in more advanced stages (recycled construction and demolition wastes and steel slag) admit, for now, just the possibility of use as granular materials in base or sub-base layers of roads. The valorization of Construction and Demolition Waste in geosynthetic reinforced embankments is almost an unexplored field.
With this research project it is intended to extend the potential application in geotechnical works of Recycled Construction and Demolition Wastes (C&DW) studying the possibility of replace the natural soils used traditionally as backfill material in geosynthetic reinforced structures.
The pursuit of this goal is based on the extensive experience of the research team in the study soil reinforcement with geosynthetics [1, 2, 3, 4]. The project team has been developing research on geosynthetic soil reinforcement, either on soil-geosynthetic interaction [3, 4, 5, 6], o  |
Summary
The reduction of non-renewable natural resources exploration has been a constant concern relating to the preservation of the environment that, simultaneously, encourages the use of alternative materials. Thus, over the last years the environmental sustainability has been demanding a progressive increase in the waste valorization in construction. This research project deals with a new application of the Recycled Construction and Demolition Waste as backfill material for geosynthetic reinforced structures (embankments with steep slopes and retaining walls).
The Portuguese Technical Committee on Waste Valorization in Geotechnical Works (CT-VROG) identified recently a group of wastes with valorization possibility in geotechnical works, among which are: steel slag; tyre wastes; construction and demolition wastes and bottom ash from municipal solid waste incineration.
Although the different types of wastes identified by the CT-VROG are in distinct research stages related to the possibility of valorization in geotechnical works, either from national or international point of view, those which are in more advanced stages (recycled construction and demolition wastes and steel slag) admit, for now, just the possibility of use as granular materials in base or sub-base layers of roads. The valorization of Construction and Demolition Waste in geosynthetic reinforced embankments is almost an unexplored field.
With this research project it is intended to extend the potential application in geotechnical works of Recycled Construction and Demolition Wastes (C&DW) studying the possibility of replace the natural soils used traditionally as backfill material in geosynthetic reinforced structures.
The pursuit of this goal is based on the extensive experience of the research team in the study soil reinforcement with geosynthetics [1, 2, 3, 4]. The project team has been developing research on geosynthetic soil reinforcement, either on soil-geosynthetic interaction [3, 4, 5, 6], one of the fundamental aspects of soil reinforcement, or in numerical modelling of geosynthetic reinforced soil structures under static loading [7, 8] and seismic loading conditions [9, 10, 11]. Taking advantage of the available knowledge and bearing in mind environmental sustainability concerns, it was considered relevant from the economic and sustainability point of view, the appraisal of the potential application of Recycled C&DW in geosynthetic reinforced structures.
According to the European List of Waste, there are Construction and Demolition Wastes classified as inert, non-hazardous and hazardous thus, their power of contamination must be evaluated. To be possible their reuse, particularly in geotechnical works, the presence of contaminants should be avoided through selective and careful demolition procedures. The physical, mechanical and environmental (the latter according to the Portuguese Decree-Law N.º 183/2009 of 10 August) of the Recycled C&DW is fundamental to appraise their valorization as backfill materials in geosynthetic reinforced structures.
After the selection of two types of geosynthetic generally used as reinforcement (geogrids and geocomposite reinforcement) their mechanical characterization will be carried out. The damage induced by the Recycled C&DW on the geosynthetics mechanical behaviour will also be analysed.
Taking into account that, in geosynthetic reinforced structures, the relative movements in the interfaces with higher occurrence probability are the pullout and the direct shear, the behaviour of Recycled C&DW/Geosynthetic interfaces will be characterized by pullout and direct shear tests. These tests will be performed for different compaction degrees of the recycled waste and different confinement pressure.
In order to evaluate the possible application of these reinforced structures in areas of high seismicity, the behaviour of Recycled C&DW/Geosynthetic interfaces will be characterized also under cyclic loading conditions.
The results of the laboratory characterization of the recycled waste and recycled waste/geosynthetic interfaces will allow the numerical modelling of geosynthetic reinforced structures using Recycled C&DW as backfill material and to take conclusions about their behaviour.
With this research project it is expected to contribute to the broadening of the waste valorization possibilities in geotechnical works, for the reduction of costs in the construction industry and for a greater environmental sustainability. |