Correct method of consolidating concrete

309R-16 7.1—Procedure for internal vibration 7.2—Judging the adequacy of internal vibration 7.3—Vibration of reinforcement 7.4—Revibration 7.5—Form vibration 7.6—Consequences of improper vibration Chapter 8—Structural concrete, p.

If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory lan- guage for incorporation by the Architect/Engineer. 309R-14 6.1—General 6.2—Sloping surfaces 6.3—Surface defects 6.4—Form tightness 6.5—Forms for external vibration 309R-2 ACI COMMITTEE REPORT Chapter 7—Recommended vibration practices for general construction, p.

As a result, pouring SCC is also much less labor-intensive compared to standard concrete mixes.

Once poured, SCC is usually similar to standard concrete in terms of its setting and curing time (gaining strength), and strength.

The incorporation of powder, including supplementary cementitious materials and filler, can increase the volume of the paste, hence enhancing deformability, and can also increase the cohesiveness of the paste and stability of the concrete.

The reduction in cement content and increase in packing density of materials finer than 80 µm, like fly ash etc.

Violetta Bryant Mather ACI Committee Reports, Guides, Standard Practices, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. Keywords: admixtures; air; air entrainment; amplitude; centrifugal force; concrete blocks; concrete construction; concrete pavements; concrete pipes; concrete products; concrete slabs; concretes; consistency; consolida- tion; floors; formwork (construction); heavyweight concretes; inspection; lightweight aggregate concretes; maintenance; mass concrete; mixture pro- portioning; placing; plasticizers; precast concrete; quality control; rein- forced concrete; reinforcing steels; segregation; surface defects; tamping; vacuum-dewatered concrete; vibration; vibrators (machinery); water- reducing admixtures; workability. 309R-2 Chapter 2—Effect of mixture properties on consolidation, p.

Several methods and techniques are available, the choice depending mainly on the workability of the mixture, placing conditions, and degree of air removal desired. This guide includes information on the mechanism of consolidation, and gives recommendations on equipment, characteristics, and procedures for various classes of construction.

309R-25 10.1—Mixture requirements 10.2—Equipment 10.3—Structural slabs 10.4—Slabs on grade 10.5—Heavy-duty industrial floors 10.6—Vacuum dewatering Chapter 11—Pavements, p.It has been demonstrated that a total fine aggregate content ("fines", usually sand) of about 50% of total aggregate is appropriate in an SCC mix.309R-1 ACI 309R-96 Guide for Consolidation of Concrete Reported by ACI Committee 309 H. 309R-35 16.1—Strength tests 16.2—Unit weight tests 16.3—Air content tests 16.4—Consolidating very stiff concrete in laboratory specimens Chapter 17—Consolidation in congested areas, p.Self-consolidating concrete is designed to avoid this problem, and not require compaction, therefore reducing labor, time, and a possible source of technical and quality control issues. Okamura at Ouchi University, Japan, at a time when skilled labor was in limited supply, causing difficulties in concrete-related industries.The first generation of SCC used in North America was characterized by the use of relatively high content of binder as well as high dosages of chemicals admixtures, usually superplasticizer to enhance flowability and stability.