Severe deterioration caused by corroding reinforcing steel in concrete structures is a major concern in the maintenance of safe and reliable infrastructure. The corrosion behavior of steel fibers and steel bars under two different aggressive conditions of modified ferroxyl gel reagent and wet-dry salt spray are described. In general, the results in the aggressive gel environment indicate that when steel fibers and steel bars were contacting each other, the initiation of corrosion in the steel fibers became considerable. When the steel fibers were electrically connected to the steel bars, the steel fibers tend to become the anode while the steel bars tend to become the cathode. The corrosion initiation, its propagation and the growth of the corrosion zones occurred in the steel fibers. The steel bars, set in the cathode zone, were protected by the surrounding steel fibers which formed a corrosion protective shield. This galvanic protection behavior by steel fibers was clearly observed in ferroxyl transparent gel. To generalize the galvanic protection behavior of steel fibers in the gel environment, the behavior of reinforced concrete specimens under an accelerated aggressive environment with both a no-fiber and fibrous concrete matrix were investigated. For this purpose, galvanized steel fibers were used. Corrosion phenomenon in the galvanized steel fibers contacting steel bars showed a sacrificial role of fibers in protecting the steel bars. No corrosion of the embedded steel bars occurred in the steel fiber-reinforced concrete matrix, while corroded steel bars occurred in the no-fiber reinforced concrete beam, thus confirming the merit of galvanized steel fibrous matrix as a protection shield to inhibit corrosion of reinforced concrete members.

Construction of transverse joints with lateral molds in RCD ( Roller Compacted Dam) method has been omitted because concrete layers are casted continuously. However, transverse joints in dam concrete should be required to prevent the occurrence of cracking. In this study, the development of a vibrating machine which can make the joints was done so that the transverse joints could be constructed in the RCD concrete. Many kinds of experiments were conducted using this machine with respect to period and direction of joint, pattern of joint material and its injection, in order to make clear the method for construction of joints. The proposed method is applicable in the actual construction of RCD concrete, and preferable results are obtained.

Personal computers (PCs) now adorn almost every office desktop and lab counter. A variety of programs are available to handle and manage data of various types. Statistical manipulation, once considered to be an arcane art of mathematicians, is now available to anyone with the inclination to learn and use it. Simple univariate statistical analyses such as mean, standard deviation, and bivariate regression, and correlation etc. are in widespread use in concrete technology. However, they only give results concerning at most two variables at a time. In the real world, the properties such as strength, frost resistance, alkali reactivity, etc depend on several mutually dependent variables. For instance, multivariate statistical techniques such as cluster analysis can group all aggregates with similar properties; factor analysis can discern what combination of tests best describe a desired property of concrete; and stepwise regression analysis can be used to predict serviceability (projected life) of concrete or aggregate based on several standard tests. Examples of the above statistical techniques are presented in a non-technical format, based on research into concrete aggregate properties as related to their service record.

Performance-based specifications are increasingly used to complement traditional prescriptive specifications in an effort to improve service life perform-ance of major infrastructure assets such as bridges. The water sorptivity of concrete, which relates to the moisture transport properties of near-surface concrete, has recently been adopted for trial application as a performance specification of concrete for bridge construction. Whilst data on water sorptivity of concretes cured under normal conditions are available, those of concrete subjected to heat curing are not yet widely available. This is particularly pertinent given that heat-cured precast structural elements are frequently used in bridge construction. This paper discusses the water sorptivity concept, its adoption in bridge specifications in New South Wales, and the performance of heat-cured concretes that could potentially be used in bridge construction.

This paper reviews investigations into a novel composite of concrete and steel, particularly as relating to seismic resistant structures. The primary novelty is that all the steel reinforcement, whether required for tensile or shear resistance, is provided as sheet rather than bar. This sheet steel is fabricated into closed box sections insi de which the concrete is cast insitu and hence fully contained. The sheet is not profil ed or specially prepared. The composi material made in this manner has been termed 1s t e Externally Reinforced Concrete, and abbreviated to ERC. The material is very strong and ductile and offers scope for simplification and cost savings in construction.