Evaluation of the Physical Properties of Unbound Base Layer Containing Recycled Aggregates

Abstract

Abstract-Construction industry is among the major contributor to the production of solid wastes, which have become a main problem of societies in present days. Asphalt and cement concrete are among the main engineering materials which are wasted in vast quantities every year due to the reconstruction and demolition of highways and buildings. Recycling of these materials would be an efficient measure for protection of environment and preservation of natural resources. In this research, the viability of using crushed waste asphalt and cement concrete as a replacement of primary aggregate in unbound base layer of flexible pavements has been investigated. Different portions of the natural aggregate have been replaced with the recycled materials and the physical properties of each mixture have been investigated. The physical properties including sand equivalent, toughness, water absorption, density, soundness and compaction have been evaluated for the mixtures. The results show that, they have potential to be used in unbound base layer. Inclusion of any amount of recycled cement concrete in unbound aggregate results in a mixture which satisfy the minimum required sand equivalent, toughness and soundness for unbound base.Index Terms-Recycled asphalt concrete, recycled cement concrete, unbound base.

In-situ strength estimation of polypropylene fibre reinforced recycled aggregate concrete using Schmidt rebound hammer and point load test

“…The building industries extract about 7.5 billion tonnes of natural aggregates annually from the earth, which has significant adverse effects on the environment. The overexploitation of natural resources and environmental degradation can be unravelled by the substitution of natural aggregates with RCA in civil and construction engineering [15][16][17][18][19][20][21][22][23]. On the other hand, the mechanical properties of recycled aggregate concrete are lower than those of the normal aggregate concrete due to the weaker bonds of adhered old mortar to RCA with cement particles, leading to decreasing the compressive strength of recycled aggregate concrete as reported by Assaad et al [24].…”

Avaliação De Ensaios De Cisalhamento Direito Em Diferentes Misturas De Solos Granulares E Residuos De Contrução Civil (Rcd)

“…Considerando que as areias utilizadas na presente pesquisa foram peneiradas com a finalidade de remover as partículas finas (siltes e argilas) e o RCD foi estritamente selecionado a partir de material de entulho (sem terra vegetal e sem detritos orgânicos), a parcela da resistência devida a coesão é decorrente da quantidade de fragmentos derivados de cimento Portland. De acordo com Fleury (2018); Nagataki et al, (2004); Silva et al, (2014) e Taherkhani (2015) ao elevar o teor de materiais derivados do cimento Portland na composição do RCD o comportamento mecânico é beneficiado, resultados justificados principalmente pela porosidade das partículas constituintes do RCD. mostraram-se menor que a dos autores citados anteriormente, pois estes incluíram frações consideráveis de limos e argilas na composição granulométrica do RCD.…”

Mechanical and Geotechnical Properties of Recycled Waste Materials: The Feasibility of using Steel Slag – Cathode Ray Tube Glass as Aggregate Replacement for Road Pavements

“…The high sand equivalent value indicates the lack of fine-grained content in the sample layer. The presence of dust (fine details) on the material surface reduces the material's resistance to wear [20].…”