International Concrete Abstracts Portal

SP-228CD This CD-ROM of Special Publication 228 contains the papers presented at the Seventh International Symposium on the Utilization of High-Strength/High- Performance Concrete that was held in Washington, D.C., USA, June 20-24, 2005. The symposium continued the success of previous symposia held in Stavanger, Norway, (1987); Berkeley, California (1990); Lillehammer, Norway, (1993); Paris, France, (1996); Sandefjord, Norway, (1999); and Leipzig, Germany, (2002). The symposium brought together engineers and material scientists from around the world to discuss topics ranging from the latest applications to the most recent research on high-strength and high-performance concrete. In the years since the first symposium was held in Stavanger, there has been worldwide growth in the use of both high-strength and high-performance concrete. In addition to more research and applications of traditional types of high-performance concrete, the use of self-consolidating concrete and ultra-high-performance concrete has moved from the laboratory to practical applications. This publication offers the opportunity to learn the latest about these developments.

This paper contains an historical review of self-compacting concrete clarifies and the original concept. Further, combinations of self-compacting concrete for high strength and durability are discussed in relation to structural concrete design, construction and maintenance, and recent development of performance-based design codes and manuals for SCC. On the competitiveness in industries, life-cycle cost is estimated for sustainable development of the infrastructure.

The utilization of high performance concrete (HPC) has increased substantially in the last decade. HPC can provide enhanced mechanical and durability properties and at the same time allow efficient placement and finishing. HPC has been utilized for cost-effective construction of bridges, buildings and pavements in most countries. The Federal Highway Administration (FHWA) has played a key role in the HPC technology transfer from research and development to routine practice for bridge and pavement design and construction. FHWA’s HPC implementation activities began in 1991. HPC implementation for highway bridges in the USA has been a success story. The success has been largely due to a long-term continuing partnership between FHWA, State Departments of Transportation, American Association of State Highway and Transportation Officials (AASHTO), local agencies, industry and academia. This paper provides an historic perspective on the HPC implementation activities since the Strategic Highway Research Program (SHRP) in late 1980’s and the subsequent programs and activities. Forty-four State Departments of Transportation have utilized HPC. HPC implementation has contributed significantly to improvements in highway infrastructure. Implementation of the long-term strategic plan developed by the industry will further contribute toward meeting the goals which include reduced congestion and improved safety, trained workforce, reduced life cycle costs and improved quality as well as reliability.

This synopsis is based on a three-part report to be published by ACI in the near future The origin of ACI’s Innovation Task Group (ITG) 4, High-Strength Concrete for Seismic Applications, can be traced back to an International Conference of Building Officials or ICBO (now International Code Council or ICC) Evaluation Report entitled “Seismic Design Utilizing High-Strength Concrete” (ER-5536). Evaluation Reports are issued by Evaluation Service subsidiaries of model code groups. An ER essentially states that although a particular method, process or product is not specifically addressed by a particular edition of a certain model code, it is in compliance with the requirements of that particular edition of that model code. ER-5536, first issued in April 2001, was generated by Englekirk Systems Development Inc. for the seismic design of moment resisting frame elements using high-strength concrete. High-strength concrete was defined as “normal-weight concrete with a design compressive strength greater than 6000 psi and up to a maximum of 12,000 psi.” It was based on research carried out at the University of Southern California and the University of California in San Diego to support building construction in Southern California using concrete with compressive strengths greater than 6000 psi. The evaluation report (ER-5536) is available on the ICC website for review. A thorough review of the above document brought up several concerns focusing on two primary areas: material and structural aspects. Irrespective of those concerns, it was evident that the evaluation report had been created because quality assurance and design provisions are needed in cities like Los Angeles to allow the use of high-strength concrete in a safe manner. Through the formation of ITG 4, ACI has assumed a proactive role in the development of such provisions with the goal of creating a document that can be adopted nationwide. The mission of ITG 4 is to develop an ACI document that addresses the application of high-strength concrete in structures located in areas of moderate and high seismicity. A structure located in an area of moderate seismicity, in modern terminology, is a structure assigned to Seismic Design Category or SDC C of the International Building Code (IBC) or the NFPA 5000 Building Construction and Safety Code. A structure located in an area of high seismicity is a structure assigned to SDC D, E, or F of the IBC or NFPA 5000. The document is to cover structural design, material properties, construction procedures, and quality control measures. It is to be written or contain example language in a format that will allow building officials to approve the use of high-strength concrete on projects that are being constructed under the provisions of ACI 301 Specifications for Structural Concrete and ACI 318 Building Code Requirements for Structural Concrete. The ITG 4 document, now in draft form, addresses the material and structural design considerations when using concretes having specified compressive strengths of 5000 psi (34 MPa) or greater that must be designed considering moderate to high seismic risk. The term “high-strength concrete,” as defined by ACI Committee 363, refers to concrete having a specified compressive strength for design of 8000 psi (55 MPa), or greater. As such, this document is meant primarily for concretes in that high strength range. However, the strength level at which concrete is considered “high-strength” depends on regional factors, such as the characteristics and availability of raw materials, production capabilities, testing capabilities, and lastly, experience. Therefore, depending on the region, the specifier may wish to selectively adopt considerations referenced in this document also when using concretes with specified compressive strengths between 5000 and 8000 psi (34 and 55 MPa). Irrespective of the location or purpose for which it is used, concrete having specified compressive strength below 5000 psi (34 M

Although highstrength concrete is often times still considered a relatively new material, its development has been gradual and continual over the last 50 years. During this period, many notable changes have occurred and continue to occur in the area of high-strength concrete technology, including the definition of high-strength concrete itself. With the increased knowledge that has been gained with respect to material availability, design methodology, and construction techniques, the feasible realm of high-strength concrete applications has grown dramatically. One of the primary objectives of ACI Committee 363 during the last few years has been to update and republish document 363R, High-Strength Concrete. This synopsis is based on a full report on high-strength concrete to be published by ACI Committee 363 (High-Strength Concrete). Estimated publication time for the new document is early 2006. The objective of the document is to present state-of-the-art information on concrete with strengths in excess of about 55 MPa (8000 psi), but not including concrete made using exotic materials or techniques. In the 1950s, concrete with a compressive strength of 34 MPa (5000 psi) was considered high strength. Today, high-strength concrete is defined as concrete with a specified compressive strength of 55 MPa (8000 psi) or higher. In many markets today, concrete having a specified compressive strength in excess of 69 MPa (10,000 psi) is routinely produced on a daily basis. Although 55 MPa (8000 psi) was selected as the current lower limit, it is not intended to imply that any drastic change in material properties or in production techniques occurs at this compressive strength. In reality, all changes that take place at or above 55 MPa (8000 psi) represent a process which starts with the lower strength concretes and continues into the highstrength realm. Items to be considered in selecting materials include characteristics of cement and supplementary cementitious materials, aggregate properties, and the effects of chemical admixtures, particularly with respect to their water reduction and hydration controlling capabilities. To ensure that required concrete strengths and other desired properties would be obtained, trial mixtures are an essential part of the process. Depending on the appropriate application, mix proportions for high-strength concrete generally have been based on achieving a required compressive strength at a specified age, many times beyond the traditional 28 days. Factors included in selecting concrete mix proportions have included availability of constituent materials, desired workability, and effects of temperature rise. Research data have indicated that the measured modulus of elasticity of high-strength concrete can vary significantly from calculated values based on unit weight and concrete compressive strength. High-strength concrete has shown a higher rate of strength gain at early ages as compared to lower-strength concrete, but at later ages the relative difference is not as significant. Information on creep and shrinkage of high-strength concrete has indicated that the shrinkage is similar to that for lower-strength concrete. However, specific creep is much less for high-strength concretes than for lower-strength concretes. The use of high-strength concrete can have significant impacts on structural design, though changes in structural behavior generally occur gradually as concrete strength is increased. Modifications to standard design equations developed for lower-strength concretes are necessary for determining the strength of axially-loaded columns, axial and flexural strength of eccentrically-loaded columns, loss of prestress in prestressed concrete beams, and minimum reinforcement requirements for flexure, shear, and torsion in reinforced concrete beams. Proposed modifications in each of these areas have been summarized in the 363R document. Significant research has been completed but consensus design e