Editors: Corina-Maria Aldea and Mahmut Ekenel

This CD contains 8 papers from sessions sponsored by ACI technical committees 544, 549, and 130 at the Fall 2012 ACI Convention in Toronto and two technical sessions at the Fall 2013 ACI Convention in Phoenix. The topics of the papers cover sustainability aspects of using fiber reinforced concrete ranging from durability and interface mechanisms of natural fiber reinforced concrete (FRC), evaluation of eco-mechanical performance of FRC, reducing carbon dioxide emissions of concrete, as well as applications of fiber reinforcement for self-consolidating concrete, bridge link slabs, extruded prefabricated elements, slab systems and fabric-reinforced cementitious matrix systems for strengthening unreinforced masonry walls.

Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-299

This research investigated as a sustainable production technique, the application of calender extrusion in the production of cement fiberboards. Use of the technique was successful for the production of non-structural building elements. The properties of the produced composites are discussed in this paper. Glass, polyvinyl alcohol (PVA), and polypropylene (PP) fibers were used. The research involved an experiment to examine the mechanical properties and microstructure of the composites. The experimental results showed that calender extrusion may be a promising method for sustainable production of thin and wide cement composites. Various forms of cement composites can be produced with this method as well. Results indicate that the mechanical properties of cement composites produced with this method are dependent on the processing direction. Processed composites have adequate screw head pull-through and freeze-thaw resistance. Higher MOR values were obtained for water cured specimens compared to air cured ones.

A major limitation of the durability of bridge decks is the area around an expansion joint which allows drainage of de-icing salts to the underlying substructure. Fiber-reinforced concrete link slabs are proposed as a more durable alternative to traditional expansion joints. This study was developed to evaluate the possibility of using more common fiber-reinforced concrete (FRC) mixtures rather than the highly designed ultra-high performance fiber-reinforced concrete (HPFRC) with fibers that has often been recommended for link slabs. In this study, the matrix proportioning and the type and volume of polymeric and steel fibers have been investigated to determine their effects on compressive, tensile and flexural strength, fracture behavior and residual strength. A standard mixture design was first optimized for workability with one steel fiber type and one polymeric fiber type. With the optimal mixture design, a selection of six fiber types were then tested for the selected mechanical properties. Although the FRCs tested did not reach the performance of the HPFRC, significant increases in performance were observed with the common fibers that could be useful in the design of a FRC link slab with the most promising results obtained with hooked-end steel macro-fibers.

This paper discusses the effect of discrete pitch-based carbon fibers on the fresh and mechanical properties of self-consolidating concrete. A total of 5 non-air entrained carbon fiber reinforced self-consolidating concrete (CFRSCC) mixtures were produced incorporating fiber volume of 0%, 0.25%, 0.5%, 0.75% and 1% carbon fibers; the water-to-binder ratio (w/b) was 0.35. The fresh properties (filling ability, passing ability, and segregation) and mechanical properties (compressive strength, splitting tensile strength, modulus of rupture and toughness) of the concrete mixtures were determined. The test results revealed that at increasing amount of volume of carbon fibers decreased the filling ability and passing ability of concrete increased. The compressive strength decreased as the volume of carbon fibers increased. However, as the carbon fiber content increased the splitting tensile strength increased. Modulus of rupture and toughness of CFRSCC mixtures also increased as the volume of carbon fibers increased. The results show that it is possible to develop good crack resistant and sustainable CFRSCC mixtures for concrete structures.

The durability performance and interface transition zone of natural fiber reinforced concrete has always been a major concern. Natural fibers due to its hydrophilic nature present a high volume variation which may cause degradation in the fiber-matrix interface. Furthermore, natural FRC may undergo an enhanced aging process, while submitted to a humid environment during which they may suffer a reduction in ultimate strength and toughness. This paper presents how the use of a matrix with low content of calcium hydroxide can mitigate the embrittlement process of natural fibers. The durability performance of the composite systems is examined and the mechanisms for the significant delay in the fiber degradation when the total amount of calcium hydroxide is reduced from the matrix discussed. Furthermore, it is shown how the repeated wetting and drying cycles affects the fiber-matrix interface. Pull-out tests were performed in sisal fiber cement composite systems to study the mechanisms that influence the fiber-matrix bond. The results showed that the use of a matrix with low amount of calcium hydroxide improved the composite durability and that the wetting and drying process reduced the water absorption capacity of the fiber and increased the fiber-matrix bond.