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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 15 Abstracts search results
Document:
SP87
Date:
September 1, 1985
Author(s):
Editor: Henry G. Russell
Publication:
Symposium Papers
Volume:
87
Abstract:
SP87 High-strength concretes are used frequently in applications requiring slender members to carry large loads or span long distances. Early applications of high-strength concrete emphasized its use to reduce column dimensions. More recently, high-strength concrete has been used to meet special project objectives such as large composite columns and stiffer structures. In turn, the use of high-strength concrete has prompted the applications of more stringent quality control requirements. This publication highlights the use, design implications, and research results of applications of high-strength concrete.
DOI:
10.14359/14044
SP87-05
Pierre-Claude Aitcin, Pierre Laplante, and Claude Bedard
Test results of a field experiment are presented where a 90 MPa (13 000 psi) silica fume concrete was used in the construction of an experimental column of a 26-storey highrise building. This concrete used a set-retarding agent in addition to a superplasticizer, had a water/cementitious ratio of 0.25 and was delivered at a slump of 250 mm (10 inches) after 45 minutes of travel. Maximum temperature was reached about 30 hours after mixing and was about 45°C (113°F) higher than the initial temperature of the fresh concrete. The thermal gradient inside the column was never greater than 20"C/m (21"F/ft) and no thermal stress problems were noted. Expressions of the modulus of rupture and modulus of elasticity, as a function of the compressive strength, are proposed. The 91 days shrinkage of this very high strength silica fume concrete was similar to that of plain concrete having a W/C of 0.40. In one concrete batch, due to a superplasticizer overdosage that resulted in an 18-hour set retardation, entrapped air macropores of 1.0 um size were created and caused a 10 MPa (1 450 psi) strength reduction at 91 days.
10.14359/6524
SP87-06
F. David Anderson
High-strength concrete (8000 pounds per square inch or above) requires that a high level of structural integrity be achieved because of the demanding applications for which it is generally selected. natural limitations of As the inher-approached, the product are close control of materials production and placement is increasingly important. Statistical methods to provide such control are outlined in this paper.
10.14359/6525
SP87-07
Arthur H. Nilson
Research at Cornell University over an eight, year period, on concrete with comprehensive strenght in the range from 6000 to 12,000psi 41-83MPa) has established a good basic for understanding the fundamental nature of the material and has also provided information on engineering properties such as moduls of elatisity, tensile strength, creep coeficient possion, ratio, rate of strength gain with age, and strain limit values. Some of these are reviewed briefly. The main purpose of the paper is to summarize more recent Cornell research dealing with the behavior of reinforced and prestressed concrete structural members, made using high strength concrete. Test have included axially-loaded members with varying amounts of spiral confinment steel, flexural critical beams with varying amounts of tensile and compressive reinforcement, and stirupps, reinforced concrete beams under sastained load of 3 years duration, shear critical reinforced concrete beams. It was found that while many provisions of the 1983 ACI code are applicable to high strength concrete materials and members certain code provisions must be reexamined, modified, or limited to insure structural saftey and servability.
10.14359/6526
SP87-08
R. N. Swamy
The paper presents a comprehensive review of the material properties and structural behavior of high strength concrete. It is shown that in practice both early development of high strength and high final strength are desirable. Further, if such concretes are to be used economically, a high proportion of their strength needs to be utilised in design. Data are presented to show that by careful selection of the type of cement and design of mix proportions, strengths of 60 to 80 N/mm2 could be obtained with normal weight aggregates in 24 hrs. With light-weight aggregates, strengths of LO-25 N/mm2 in 12 hrs. and of 25-45 N/mm2 in 24 hrs. are reported. The paper then discusses the engineering properties of such concretes such as elasticity, shrinkage and creep. The implications on structural behavior, when high working stresses of 30 to 50% of the cube strength are used, are then discussed in terms of transmission length, prestress losses, short term structural behavior and longterm structural behavior. Particular emphasis is given to those aspects that need to be considered in design.
10.14359/6527
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