The effect of material constituents on the performance of fiber reinforced cementitious thin sheets was studied in order to examine the possible trade-off between cost and performance in cement-based building product development. A variety of materials were incorporated into fabricating cementitious thin sheets. The variables included types of fibers (glass, polyethylene terephthalate, polyolefin, or polyvinyl alcohol), types of sand (marble, silica or fly ash) and percent content, mixing method (dispersive or non-dispersive), latex types (MMA or SB), cement types (Type I or Type III), mineral additives (metakaolin or silica fume) and curing conditions (moisture or steam). Twelve batches of thin sheets with 3% fibers by volume for each were prepared by extrusion processing and three-point bending tests were conducted to evaluate the strength and toughness. The purpose of the study was to establish several mix designs for extrusion production of high performance fiber reinforced cementitious thin sheets at compatible cost.

The steel free bridge deck slab technology has seen its real-life applications in a span of less than ten years from its initial conception. Indications are that more and more bridges will be built using this concept around the world, especially in places where corrosion of reinforcement is a serious concern. In this paper, results of an experimental project carried out at the University of British Columbia, where a full scale bridge deck was tested with carbon fiber reinforced cement (CFRC) permanent formwork, are described. The bridge deck had 0.4% of fibrillated polypropylene fiber reinforcement but no traditional steel reinforcement. The carbon fiber used in the formwork was a pitch-based fiber with a moderately high modulus of elasticity and tensile strength. The deck slab was tested at various locations under a simulated concentrated wheel load and the load vs. deflection characteristics were recorded. While the bridge deck failed, as expected, in a punching shear mode at a load several times higher than the design load, the bond between the CFRC formwork and the concrete deck was identified as a weak link in the system

SP190 The 11 papers in this Special Publication were presented at the ACI Spring Convention in Chicago, Illinois in March 1999, and represent worldwide advances in the development of high-performance fiber reinforced thin sheet products. The applications addressed include curtain walls, pipes, roof tiles, and repair/retrofit of existing structures. The manufacturing processes are discussed as well as the variety of natural and manufactured materials used.

The use of GFRC using the low shrinkage, low alkaline cement for GFRC (CGC) in construction projects has recently been increasing in Japan because of its high durability of bending strength and its excellent dimensional stability. In the case of GFRC using CGC, however, rather strict steam curing condi-tion is necessary when it is manufactured. On the other hand in the case of GFRC using the super low contractile admixture (NSR), no special cure is necessary. NSR consists of calcium aluminate and inorganic sulfate. GFRC-NSR is composed of ordinary port-land cement, NSR and water-quenched blast furnace slag. GFRC-NSR also shows excellent bending strength and dimensional stability. This paper describes optimum mixture proportions of GFRC-NSR and various properties of GFRC-NSR such as bending strength after hot-water accelerated aging, bending strength after dry-wet cycles accelerated aging, drying shrinkage, change in length after dry-w-et cycles, freeze-thaw resis-tance, and pull-off strength of flex anchor.

The durability of two extruded thin sheet PVA fiber reinforced cement composites were investigated. The baseline composition contained silica fume and the other replaced the silica fume in the baseline composition with OPC. Compositions were subjected to aging in a 50% relative humidity room, immersion in a 50?C waterbath, and exposure to freeze/thaw cycling. Samples were tested primarily in the saturated condition and less frequently in the dry condition. Strength and toughness values were obtained from 3-point flexural and notched tensile tests. The effects of aging, silica fume content, and testing condition were considered. Each composition, tested in both the saturated and dry conditions and tested for all types of aging, experienced similar trends: a decrease in flexural strength and flexural first crack stress, an increase in tensile strength and tensile first crack stress, and a decrease in toughness values. Although both the non-aged and aged specimens experienced fiber pull-out, the mechanism of bond failure appears to be different. The contribution of silica fume was not significant as far as durability is concerned. Strength increased with drying, and toughness generally decreased.