Valorization of new natural and recycled materials in the road construction in Algeria

摘要

These recent years, the development of the civil engineering and especially the public works sectors in Algeria requires large amount of aggregates. Therefore, the abusive uncontrolled extraction of materials send out distress signals on the over-exploitation and reduction of the usual natural sources of aggregates, particularly alluvial deposits. Indeed, this can certainly maximize the risks of environmental contamination and threaten the aggregates supply continuity of projects, therefore seriously disturbing the development of the public work sector. For those reasons, the exploitation of new aggregates sources and the search for new local materials (natural or recycled materials) are urgently needed and seem to be a promising solution for sustainable development. Indeed, many natural materials such as (schist, marl,aEuro broken vertical bar) have been investigated in this area, given their availability and ease of extraction. Also, tons of inert wastes (concrete debris, glass debris,aEuro broken vertical bar) are generated from various human activities and abandoned in nature (along the roads) or buried in landfills where they surely represent contamination threats to ground water, while, these materials can be recovered and reused as alternative aggregates in important industrial sectors such as civil engineering and public works. The present experimental study is conducted in this context. It aims at valorizing local natural materials (marl) and recycled materials (glass debris) in road construction. Indeed, marl is among the most available materials in Algeria, it represents over 40% of the soils of Great Kabylia (Tizi-Ouzou). It is close to the surface (accessibility), with thicknesses exceeding 1000 meters (availability). Glass debris are also among the most available types of wastes (found in dumps and landfills). It is widely used in many industrial activities such as packaging, decoration, construction, and therefore it generates a lot of inert waste which take about 5000 years to decompose. For those reasons (large amounts and lengthy decomposition), several studies have been carried out for the glass possible reuse in civil engineering, especially in concrete and roads. To achieve this work, samples are prepared in the form of mixtures of marl with different proportions of glass debris (0, 10, 20, 30 and 40%). They are then submitted after identification to the main mechanical road tests, namely: compaction with modified Proctor tests in order to assess their maximal dry density, penetration with CBR tests (California Bearing Ratio) to evaluate puncture strength immediately under the circulation of vehicles during the construction of pavements or after soaking under water for 4 days (96 h), representing the worst humidity conditions on construction site. The samples are then subjected to direct shear tests using Casagrande shear box to assess their shear strength under traffic, especially during acceleration and braking of heavy vehicles. Finally, they are subjected to fragmentability, degradability, Los Angeles and micro-Deval tests to evaluate the evolution of the grains under different mechanical efforts (traffic, climatic and hydro-geological conditions). The experiments carried out have shown very remarkable results. Unlike the unfavorable behavior showed by the marl or the glass alone; their combination as mixtures presents very interesting mechanical characteristics under the different tests.