Title: Sustainability And High-Performance Of Concrete – A Review
Author(s): Tarun R. Naik; Fethullah Canpolat and Giacomo Moriconi
Publication: Symposium Paper
Appears on pages(s): 43.1-43.10
Keywords: Compressive strength, Chloride-ion penetration, Permeability, High-performance of concrete, High-quality concrete
Concrete durability-related properties are known to be negatively affected due to expansion and cracking that result from factors such as freezing and thawing actions, alkali-aggregate reactions, sulfate attack, corrosion of the reinforcement, shrinkage, and other similar factors. Durability, and, therefore, sustainability of properly designed and constructed concrete structures depends primarily upon the quality of the materials of construction and other simple, but critical, steps. Concrete construction can last 100 years or more if five simple "steps" are followed: (1) materials selection; (2) structure design; (3) construction; (4) quality management; and, (5) timely evaluation, maintenance, and repairs. This is a holistic approach. Most mistakes are made in not satisfactorily following Steps 4 and 5. Conventional mixture proportioning technique used for production of high-strength concrete does not guarantee long-term durability of concrete. Concrete mixtures must be proportioned to attain desired workability, high-dimensional stability, high-strength, and high-durability related properties; i.e., high-quality concrete (HQC). However, mixture proportioning requirements for HQC must be varied according to the type and expected use of the concrete construction. HQC mixtures must have high-quality constituent materials: durable aggregates, low heat of hydration cement, mineral additives, and chemical admixtures. Furthermore, the mixing water must be minimized (i.e. a low water to cementitious materials ration, W/Cm). A strict quality control is also needed in various aspects of the production of HQC. Research activities conducted at the UWM Center for By-Products Utilization (UWM-CBU), CANMET, and elsewhere, have demonstrated that HQC mixtures can be proportioned to obtain strength in excess of 100 MPa (14,000 psi) and service life of 100 plus years.