Repair of Berth Faces at Port of Montreal with Fiber-Reinforced Shotcrete
D. R. Morgan, A. Lobo, and L. Rich
Appears on pages(s):
durability; polyolefin fiber; repairs; shotcrete; silica fume;
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.