Synergistic use of milled waste glass and recycled aggregate towards a sustainable concrete-based infrastructure.

摘要

A novel concept of using milled waste glass, as partial replacement for cement, to overcome the drawbacks of recycled aggregate concrete was investigated. Based on experimental investigations of the structure and properties of concrete materials, it was found that waste glass, when milled to micro-scale particle size, undergoes pozzolanic reactions with cement hydrates, forming secondary calcium silicate hydrate (C-S-H). These reactions bring about favorable changes in the structure (including pore system characteristics of the hydrated cement paste and the interfacial transition zones in normal and recycled aggregate concrete.;Use of milled waste glass, as partial replacement of cement, produced significant gains in the resistance to moisture sorption and chloride permeation, durability under freeze-thaw and abrasive effects, dimensional stability and mechanical properties of normal and particularly recycled aggregate concrete. Milled waste glass was also found to suppress alkali-silica reactions. Unlike normal pozzolanic reactions, those involving glass do not reduce the alkalinity of cement paste; this is favorable to the chemical stability of concrete and its protection of reinforcing steel against corrosion. Field investigations confirmed the compatibility of recycled glass concrete with conventional concrete production and construction techniques, and verified the excellent performance of pavement sections made with recycled glass concrete after two years of natural weathering.;Numerical studies were conducted in order to predict the service lives of concrete pavements and bridge decks exposed to sulfate or freeze-thaw attack in different climatic conditions. Partial replacement of cement with milled waste glass in normal and recycled aggregate concrete produced significant gains in service life due to the improved resistance of concrete to the transport of moisture and deleterious ions.;Recycling of waste glass in concrete can divert large quantities of the market-limited (mixed-color) waste glass from landfills for value-added use as partial replacement for cement, enable effective use of recycled aggregates in concrete, yield major cost and energy savings, and enhance the long-term performance, the life-cycle economy and the sustainability of concrete-based infrastructure systems.