Performance-Based Specifications of Workability Characteristics of Prestressed, Precast Self-Consolidating Concrete—A North American Prospective

Abstract

Adequate selection of material constituents and test methods are necessary for workability specifications and performance of hardened concrete. An experimental program was performed to evaluate the suitability of various test methods for workability assessment and to propose performance specifications of prestressed concrete. In total, 33 self-consolidating concrete (SCC) mixtures made with various mixture proportioning parameters, including maximum size and type of aggregate, type and content of binder, and w/cm were evaluated. Correlations among various test results used in evaluating the workability responses are established. It is recommended that SCC should have slump flow values of 635–760 mm. To ensure proper filling capacity greater than 80%, such concrete should have a passing ability that corresponds to L-box blocking ratio (h2/h1) ≥ 0.5, J-Ring flow of 570–685 mm, slump flow minus J-Ring flow diameter ≤75 mm. Moreover, Stable SCC should develop a column segregation index lower than 5%, and rate of settlement at 30 min of 0.27%/h for SCC proportioned with 12.5 or 9.5 mm MSA. It is recommended that SCC should have a plastic viscosity of 100–225 Pa·s and 100–400 Pa·s for concrete made with crushed aggregate and gravel, respectively, to ensure proper workability.

Using aggregate flowability testing to predict lightweight self-consolidating concrete plastic properties

“…In the decades that followed, substantial research has been conducted and SCC has gained worldwide acceptance as an important civil engineering material. SCC has a number of advantages over non-SCC such as: uniform placement without vibration or additional compaction, smaller and more complex shaped structural elements, greater quality of surface finishes, and longer hours for construction in urban areas due to noise reduction [1,2]. The initial cost of the SCC materials is higher due to the increased amount of fines particles and costs for high dosages of chemical admixtures; however, SCC material costs can be offset by the advantages listed above.…”

Physical and mechanical characteristics of sustainable self-consolidating concrete incorporating high volume fly ash and cement kiln dust

“…The concrete stayed at rest in the mixer for 1 minute to permit any big air bubble captured throughout mixing to rise to the surface. The concrete was then remixed for 1 minute [27]. After that the concrete was casted in the moulds without any vibration and instantaneously covered with plastic wrap and kept undisturbed for 24 hr.…”

Factorial Design Approach in Proportioning Prestressed Self-Compacting Concrete

“…The ranges of these variables were selected to cover a wide scope of mixture ingredients. The choices of the w/cm and binder type were based on the results obtained in the previous parametric study [ 11 ]. A low w/cm was included to secure superior mechanical performance and the higher w/cm for better workability.…”

“…Although the mix design of concrete is critical to its workability and performance, adequate selection of material constituents is a key factor in the optimization process of a concrete mixture that can achieve adequate performance and service life [ 11 , 12 ]. Material characteristics and mix design of SCC have a marked effect on all aspects of SCC production and placement, and on the fresh and hardened properties of the concrete [ 13 , 14 ].…”