International Concrete Abstracts Portal

This CD-ROM consists of papers that were presented at a session sponsored by Committee 549 at the Fall 2007 Convention in Fajardo, Puerto Rico. The objective of the symposium was to have a state-of-the-art review on the development of fabrication methods for cementitious products and explore their potential market opportunity in residential and industrial building applications. 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-260

Within the framework of an AiF research project, production methods for the serial batch production of building elements made of textile reinforced concrete were examined. The research work comprised the manufacturing techniques of laminating, casting, spraying and spinning as well as combinations of these methods. In the beginning the main focus was directed on the production and manufacturing technique with the adjustment of fine grained concrete and fabrics to the respective production technique and the development of spacers. Afterwards building elements were manufactured applying selected production techniques to be able to examine the entire manufacturing process of the building elements. The entire manufacturing process included the choice of the suitable production technique, the design of the building elements, the pre-confectioning of the fabrics, the production of the building elements as well as their testing and the discussion of the results. This paper presents the results of the research work. At first the production methods are explained. Afterwards the entire manufacturing process is exemplarily described for the production of spun concrete tubes as well as for elements of an integrated formwork.

Carbonation curing of cellulose fiberboard made by slurry-dewatering process was studied to examine their CO2 uptake capability, immediate carbonation strength and long term strength after subsequent hydration. Influencing parameters on CO2 uptake and strength gain were discussed. They included compact forming pressure, drying time, drying temperature, carbonation duration, fiber/cement ratio and water/cement ratio. It was found that cement bonded cellulose fiberboards had excellent carbonation capacity. The percent carbon uptake ranged from 13.5 % to 23.6%, based on cement content and process conditions. High degree of carbonation significantly improved early age strength and had no detrimental effect on the subsequent hydration strength. To promote more CO2 uptake and higher strength gain, carbonation rate should be controlled. This can be achieved through system optimization. Carbonation curing has shown the potential to replace traditional autoclaving and gain technical, economical and environmental benefits.

The housing industry is a critical component of the American economy representing about 4% of the economic activity of the nation. Light weight structural insulated panels (SIP) for walls and roofs are gaining wide acceptance in the construction industry because of the advantages they offer. Energy savings, sound abatement, disaster resistance and durability are just a few of the benefits of buildings constructed with SIP. A variation of these panels is a structural concrete insulated panel (SCIP), commercially referred to as the MetRock (MR) Panel system. The aim of this paper was to study the flexural behavior of the SCIP system and discuss the manufacturing and construction aspects of the SCIP system. An analytical method for estimating the panel’s flexural strength was developed and a step-by-step design procedure is provided to predict the load carrying capacity of the panels and provide the engineer with a reliable tool for designing the panels. An experimental program was conducted and the results were compared to the analytical method for different size panels. The test results were in close agreement with the estimated values thus verifying the validity of the analytical approach.

This paper presents an analytical model developed to predict the flexural response of a novel thin-walled pole comprising centrifugally cast concrete into a glass fiber reinforced polymer (GFRP) circular tube. The tube acts as a permanent form and at the same time is effectively considered as reinforcement for the pole by means of layers of fibers oriented in the longitudinal and circumferential directions. The model combines cracked-section analysis, the classical lamination theory of composites and non-linear extended strain softening concrete models, through a layer-bylayer approach to account for the inherent complex geometry of the section. The model was verified using experimental results and showed good agreement. It was then used in a parametric study to establish the optimum concrete wall thickness for FRP tubes of different proportions of fibers in the longitudinal and circumferential directions as well as tubes of different wall thicknesses. It was shown that the optimum concrete wall thickness is highly dependent on the FRP tube composition. It increases as the fraction of longitudinal fibers increases, or as the wall thickness of the tube increases.