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 study deals first with the deterioration of glass fiber in mortar due to the alkali of cement and how to improve the deterioration of the glass fiber in mortar using special admixture of blast furnace fume (BFF). The deterioration is estimated by an accelerated test for flexural strength of mortar stored in water at 80 °C for 3 weeks. Secondly, the deterioration of mortar due to sulfuric acid attack using blast furnace fume(BFF) is investigated. Dust collected from the top of Chinese small-sized iron blast furnaces is called BFF in Japan , and is used as admixture for high strength concrete in China. BFF is composed of very fine particles with spherical shape. Its average grain size is several micrometers in diameter. Test results of this first study shows that the deterioration of glass fiber in mortar due to alkali is not improved by using BFF alone but is significantly improved by using both BFF and blast furnace slag (BFS) or silica fume (SF). Concerning acid attack, it is found that the deterioration of mortar in dilute sulfuric acid is significantly decreased by using both of BFF and BFS or SF.

Construction of modern structures and reconstruction of the existing onesimpose very demanding requirements for the quality of used materials. Highperformance hybrid fibre reinforced concrete appears to be a material of great importance in the future. An innovative type of this concrete was tested and its properties were compared with those of reactive powder concrete, high performanceconcrete and plain concrete. Compressive strength, flexural strength, toughness and modulus of elasticity were measured. For the purposes of toughness testing, an acousticemission technique was used to detect cracking and fracture properties.

Several years ago, a new generation of concrete, the ultra high performance fibre-reinforced concretes have been introduced. We have developed a range of products based on such new technology. The ultra high performance concrete developed is the result of an optimisation of the nature and the composition of different raw materials. It is composed of a premix, a new superplasticizer, fibres and water. Otherwise, numerous investigations have been carried out on this ultra high performance concrete such as plasticity, workability time, compressive strength, flexural strength, shrinkage, coating system, bonding, …. The ultra high performance concrete described in this paper was used for the carrying out of the tollgate roof of the viaduct at Millau, Southern France. This structure is part of the A75 motorway from Clermont-Ferrand to Montpellier.

Reactive powder concrete (RPC) is a new type of ultra-high strength and high ductility concrete first developed in the 1990’s in France. It is recognized as a revolutionary material that provides a combination of ductility, durability, and high strength. In this paper, the RPC mixture proportioning is optimized and its mechanical properties, such as compressive strength, flexural strength, elastic modulus, and its durability, are tested and discussed. Based on the optimal mixture proportion, eight simply supported RPC beams are made and tested. The mechanical properties of RPC beams, including section deformation, load-displacement relationship, failure forms, crack distribution, crack extension, and ultimate flexural capacity, are discussed. It is concluded that RPC is an excellent material with high strength and durability. The section deformation of RPC beams is accordance with the assumption of a plane cross-section. Steel fiber is important to control the crack extension and to improve the ductility of RPC beams. For RPC beams without reinforcement, only one main crack occurred during the failure process, and for RPC beams with reinforcement there were many subordinate cracks created near the main cracks. If the amount of reinforcement is increased, the numbers of subordinate cracks will increase.