"This publication contains the papers originally presented in a symposium on the topic of thin reinforced cementitious products organized by ACI Committee 549, Thin Reinforced Cementitious Products and Ferrocement, during the ACI 2003 Spring Convention held in Vancouver, British Columbia, Canada. The symposium explored current state-of-the-art and recent advances in material science, manufacturing methods, and practical applications of thin reinforced cementitious products. The topics covered in this publication include material science of textile reinforced concrete, use of textile reinforced concrete for integrated formwork and exterior cladding panels, prestressed thin-sheet concrete products, ultra-high-performance thin precast concrete products, production of concrete tubes by centrifugation method, freezing-and-thawing durability of commercial fiber-reinforced cement boards, structural evaluation of cement-skin sandwich building systems, microwave accelerated curing method for producing precast cementitious products, history of glass fiber-reinforced concrete (GFRC) products, and modeling of cement-based laminate composites." Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP224

Techniques for modeling the mechanical response of thin section cement-based composites intended for structural based applications are presented using a micromechanical approach. A layer model is used and the property of each layer is specified based on the fiber and matrix constituents in addition to the orientation and the stacking sequence in each lamina. The overall axial and bending stiffness matrix is obtained using an incremental approach which updates the material parameters. The simulation is conducted by imposing an incremental strain distribution, and calculating the stresses. A stress based failure criterion is used for the three failure modes of initiation of cracking, ultimate strength of matrix, and ultimate strength of lamina. As the cracking saturates the specimen, it results in a gradual degradation of stiffness. A continuum damage model based on a scalar damage function is applied to account for the distributed cracking. The model predicts the response of unidirectional, cross ply and angle ply laminae under tensile loading in longitudinal and transverse directions. The load-deformation responses under tension and flexure are studied. It is shown that by proper selection of modeling approach, parameter measurement, and theoretical modeling, a wide range of analysis tools and design guidelines for structural applications of FRC materials are attainable.

Thin, fiber reinforced cementitious products offer a useful balance of properties such as strength, toughness, environmental durability, moisture resistance, dimensional stability, fire resistance, aesthetics and ease of handling and installation. For more than 30 years, AR glass fibers have been at the forefront in the development of new applications of such products throughout the World. Glass Fiber Reinforced Concrete [GFRC] is a thin, cement composite based on AR glass fibers with an excellent strength to weight ratio. Extensive early laboratory work produced a test method for determining long term strength. The validity of this work has been proven by the large number of buildings clad with GFRC, as well as a vast range of other GFRC products, used over a this 30 year period. This paper explains the fundamental principles behind GFRC and gives examples of some of its uses. These applications range from high quality, architectural wall panels and decorative elements through to modular buildings down to low cost channel sections and utility components. New developments and techniques will also be discussed.

The use of microwave technology to speed up the production of precast ferrocement secondary roofing slabs is explored in this paper. In particular, the use of discrete on-off microwave curing regimes and the effects of such regimes on the strength and durability of the ferrocement slabs are investigated. By a regime of on-off microwave application to maintain the temperature of the slab within a specified range during microwave curing, overheating of the slabs can be avoided. High early age strengths were attained in slabs cured using such regimes, with no strength loss at 28 days. In addition, the durability of such slabs need not be compromised. The use of an appropriate reduced power level during the later stage of the curing process was found to result in a marginal improvement in the near surface quality without any reduction in early age strength.

Hybrid fiber reinforcement of cement composites is rapidly emerging as an innovative and promising way of improving mechanical performance and durability of cement-based materials. In the present paper, fracture behavior of medium, high and very high strength mortars reinforced with hybrid fibers was experimentally studied by using contoured double cantilever beam specimens. Different combinations of small steel fibers and fibrillated polypropylene micro-fibers are investigated. These composites are very suitable for thin sheet products such as roofing sheets, tiles, curtain walls, cladding panels, permanent forms, etc. Aim of the paper was to study the influence of matrix strength, fiber type and fiber combinations on the fracture toughness of the resulting fiber reinforced mortars. Results indicate that some combinations of fibers and matrix strengths exhibit a higher resistance to crack growth and evidence the contribution of polypropylene fibers to mortar toughness.