Jetty structures were constructed at Kobe Port as part of the reconstruction project after Hanshin Great Earthquake in 1995. In this jetty structure, straight and oblique base piles were jointed with a precast slab in the field to shorten the work period. This paper presents the results of experiments carried out in a laboratory, the full scale filling test using a super workable concrete applied to the joints of structure, and the concrete quality. Super workable concrete containing a viscosity agent, gypsum, and ground granulated blast-furnace slag was used to satisfy the requirements for its high filling ability, minimized bleeding, and reduced shrinkage. Super workable concrete was produced and placed from a concrete plant ship in this construction.

High Strength High Performance Concrete (HSC/HPC) has been used in a number of projects in several countries. Research on HSC/HPC is currently in progress in a number of centres. The author and his research team at Curtin University have conducted research on the behaviour and the strength of HSC/HPC structural members. The research comprised experimental and analytical studies on columns under eccentric compression, structural walls subjected to horizontal and vertical loads, bond strength and bar splice lengths, shear strength of beams, concrete filled steel tubular composite columns, and long-term deflection of flexural members. The test specimens were made using the HSC/HPC supplied by a commercial readymix plant in Perth, Western Australia. The research was funded by Australian Research Council Large Grants and by the industry. This paper presents a summary of the results obtained from the research and recommendations for design. .

Electrochemical chloride extraction is a rehabilitation process aimed at reducing the chloride levels of contaminated reinforced concrete structures to below the critical values for corrosion of the reinforcing steel (rebar). While this has been demonstrated to be feasible, the effects of the treatment on the microstructure and the mechanical properties of the concrete have not yet been adequately documented. This research attempts to characterize the changes in concrete and mortar, particularly at their interface with the rebar, due to an extraction treatment. To this end, concrete specimens with 3.0% Cl by mass of cement, and mortar specimens with 2.0% Cl by mass of the cement were cast, cured and, after various exposures, subjected to electrochemical chloride extraction treatments typical of those applied commercially. The mortar specimens were examined metallographically while concrete specimens were subjected to mechanical durability studies. It is clear from this study that the structure and mechanical properties of the concrete immediately adjacent to the reinforcing steel are severely degraded by the electrochemical extraction treatment. It remains to be seen if the damage is permanent or if there is a subsequent redistribution of ions which could ameliorate the structure and, hence, the properties.

A natural amorphous silica with a purity of approximately 90% is mined from an extensive geothermal deposit near Rotorua, New Zealand. After refining and processing to remove impurities, the ‘Microsilica 600TM’ has properties which comply with Australian Standard AS 3582 Part 3 ‘Silica Fume’ as a supplementary cementitious material for use with portland cement. The performance characteristics of concrete incorporating the ‘Microsilica 600’ were evaluated at two cement levels of 320 and 400 kg/m 3 and two silica addition levels of 7 and 10%. Properties evaluated were compressive strength, tensile strength, concrete shrinkage, sulfate resistance, resistance against chemical attack, abrasion resistance, and chloride permeability. Performance improvement compared favorably with published data on concretes incorporating processed ‘conventional’ silica fume.

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.