Concrete berth faces in the St. Lawrence river at the Port of Montreal constructed in the early 1900's are undergoing continuing deterioration from the combined effects of frost damage, alkali aggregate reactivity and in some areas attack from deicing chemicals stored on the adjacent wharves. In some places the concrete is turning to rubble, and a major retrofit program is required to restore the berth faces to a serviceable condition. Both cast-in-place reinforced concrete and anchored and tied-back fiber reinforced shotcrete remedial potions are being evaluated to establish the most technically sound and cost-effective remedial alternatives for this work. This paper describes a prototype construction project in which about two thirds of a berth face, 122m long and 7.1m. High, was repaired with a synthetic fiber reinforced shotcrete and the remaining third with a steel fiber reinforced 25mm long by .38mm diameter added at an addition rate of 1.25 percent by volume of the shotcrete. The deformed steel fiber 38mm long was added at an addition rate of .75 percent by volume of the shortcrete. The shotcrete used was air entrained, silica fume modified, supplied by transit mixers from a central-mix plant and applied by the wet-mix plant and applied by the wet-mix shotcrete process. This paper describes the remedial design, shotcrete mixture designs, preconstruction mock-up production and quality control testing and provides a summary of construction quality control test results. Test results reported include plastic shotcrete properties such as as-batched and as-shot slump and air-content, compressive strength, boiled absorption and volume of permeable voids and toughness. The behavior of the shotcrete repairs is being monitored service is described. Comparative data is provided regarding the relative costs of the cast-in-place reinforced concrete and fiber reinforced shotcrete alternatives.

The performance of wollastonite-reinforced portland cement-based binders hydrated in saturated Ca(OH)2 solution, 1N NaOH solution, 1N KOH solution, distilled water and saturated moist air was evaluated as a precursor to the development of a test for assessing the durability of these composites. The cementitious binders are made of cement and silica fume. The effect of the different solutions on the mechanical behavior and microstructural characteristics of the systems investigated at 24 degrees Celsius and 80 degrees calicoes was determined. Porosity and pore structure determinations were made using mercury intrusion porosimetry, helium pycnometry, and isopropyl alcohol saturation techniques. Flexural strength and fracture toughness behavior was also determined. Pore structure modifications, leaching effects and mechanical test results were stability of wollastonite micro-fibers in cement binders. Wollastonite microfiber appears to merit serious consideration as a candidate reinforcement for the development of new composite systems.

A large variety of materials and techniques are available to increase strength of existing concrete structures in an effort to extend their service life. The way to make repaired and strengthened concrete structures durable is to ensure that the new composite system is "tailored" to serve the intended service life, and that the composite human system, the team involved with a project, is knowledgeable and experienced enough to recognize the complexity of their task. The paper reviewed traditional methods and also offers a review on the use of advanced composite materials for strenghening existing comcrete structures. The advantages and limitations of different techniques are presented. It is concluded that, in the futrue, advanced composite materials will be widely used for repair and strengthening. To achieve this, it is vital that research and engineering education in cement-based and advanced composite materials are improved.

Slurry infiltrated mat concrete (SIMCON) has recently emerged as a high performance steel fiber cementitious composite. Flexural strength, ductility and toughness of SIMCON were found to be superior to conventional steel fiber concrete. Being mechanically rolled at the plant, application of SIMCON in the field is facilitated. With high strength, ductility and ease of construction, SIMCON holds potential for application in repair of deteriorated highway bridge coupled with harsh weather conditions and presence of deicing chemicals result in continuous need for repair and rehabilitation. This paper discusses the potential advantages of SIMCON in repair applications. Mechanical properties of SIMCON including tensile stress-strain behavior and flexural load-deflection relation are reviewed. Investigation of the interfacial bond strength of SIMCON overlay and concrete substrate is focused in this project. To assess bond between plain concrete substrate and SIMCON, the effect of shear nails and latex was studied. Furthermore, air permeability of SIMCON via nondestructive testing was studied. Test results indicate the potential of SIMCON for use in repair and rehabilitation of pavements and bridges.

This paper suggests design guidelines for seismic retrofit of non-seismically designed reinforced concrete frames using High Performance Fiber Reinforced Concretes (HPFRCs), I.e., Slurry Infiltrated Mat Concrete (SIMCON) and Slurry Infiltrated Fiber Concrete (SIFCON). The following retrofit schemes are addressed: (1) column retrofit with either discontinuous or continuous SIMCON jackets, and (2) joint retrofit by either "internal" retrofit with prestressing bars or "external" SIMCON jacketing. Validity of the suggested guidelines was experimentally verified by testing a series of seismically retrofitted non-ductile beam-column sub-assemblages. Experimental data indicate that the suggested design procedure was appropriate for the retrofit design of the specimens. Additional experimental and analytical investigations are suggested to confirm the validity of proposed design approach for different beam-column connections. The paper focuses on the design procedure. Key pieces of information on the experimental investigation are only reviewed here and are presented in detail elsewhere [1].