High-Volume Recycled Materials for Sustainable Transportation Infrastructure.

摘要

The objective of this study is to investigate the feasibility of using high performance concrete made with high-volume of recycled materials in transportation infrastructure. The main focus was to develop mixtures for rigid pavement construction. A variety of fine and coarse recycled concrete aggregates (RCA) were investigated. The feasibility of replacing 50% of Portland cement with industrial by-products and supplementary cementitious materials (SCMs) was also evaluated. Experimental program was conducted to quantify the effect of concrete mixture design and RCA characteristics on mechanical properties, drying shrinkage, cracking potential, and durability of concrete. The development of a database and analysis using artificial intelligence was considered to quantify the properties of concrete as a function of RCA characteristics. Results were validated during a field implementation project in Missouri. The project involved the design of the concrete mixtures, the sampling and testing of concrete at the job site, and in-situ monitoring of deformations of rigid pavement section under controlled traffic loading and environmental effect. Testing was also conducted on large-scale reinforced concrete beams cast with selected concrete mixtures to investigate the structural performance of such green materials. In general, satisfactory performance was achieved for the key properties of concrete for infrastructure applications, indicating that concrete with 50% SCM and over 50% coarse RCA can be considered for the production of sustainable and high performance concrete. The 120-day shrinkage of such concrete can be limited to 450 muepsilon, while meeting the design criteria for mechanical properties and durability and exhibiting no cracking under re-strained conditions up to 35 days.