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An experimental investigation was conducted on the shear behavior of deep beams made with steel fiber reinforced high performance concrete (HPC). Twenty-six beam specimens with various shear span-effective depth ratios, steel fiber contents, amounts of vertical and horizontal web reinforcements were tested under static loads. In addition to the strength test, extensive instrumentations were designed for the measurements of average strains of reinforced concrete in the shear span and strains of web reinforcements. The web-shear cracking initiated as the first inclined shear crack. About 30% increase in the inclined shear strength and 25% increase in the ultimate shear strength can be achieved with addition of 1 .O% steel fiber for specimens having a/d= 1 .5. The strain of vertical web reinforcements became negative and the horizontal web reinforcements were stretched to yield state for specimens having a/d ratios approach 0.5. The measured load-deformation relationships of reinforced concrete and strains of web reinforcements were compared with the prediction of the softened truss model of steel fiber reinforced concrete proposed by other investigators. Good correlation was found from the comparisons.

The chemical and petrochemical industries that process chemical and petrochemical products manufacture, store, and transfer a number of liquids that are hazardous to the environment and particularly to the groundwater. In Germany, uncoated concrete may be used only as a secondary barrier for handling water-hazardous materials. Development and optimization studies were carried out to reduce the permeability and increase the ductility of concrete for this application. Concretes with styrene-butadiene-based polymer dispersions and silica fume were produced to reduce the permeability, and concretes with limestone or expanded clay instead of Rhine gravel to improve ductility. The mechanical behavior of the concretes was characterized by determining the stress-strain curves under tensile and compressive loading and the stress crack-opening curves. Resistance to environmentally hazardous liquids was tested using a special penetration test standardized in Germany. Various organic liquids, each representing a main chemical group and of differing water solubilities and viscosities, were used as test media.

One of the techniques proposed to improve the durability performance of concrete in aggressive environments is to use quality concrete. Much research has shown that cement composition also has a significant effect on concrete durability in sulfate-bearing soils/groundwaters and in chloride-corrosive situations. High C 3A cements have been found to be superior in terms of protection against corrosion of reinforcement, although they have a lower sulfate-resistance performance. In many situations, such as marine and Sabkha environments, chlorides and sulfates occur concomitantly and operate against concrete durability simultaneously. This study has been carried out to evaluate the sulfate resistance and chloride penetration performance of high-strength concrete. Two high-strength concrete mixes in the range of 60 to 75 MPa were designed first by using a superplasticized concrete of 0.36 water-cement ratio (w/c) and second by replacing 10 percent cement by silica fume. The control for comparison is a 25 Mpa concrete made with a 0.58 w/c. Type I portland cement has been used to provide higher chloride-binding capacity and, hence, better corrosion protection. A mixed sodium and magnesium sulfate environment has been used to evaluate sulfate resistance. High-strength concrete made with silica fume blending showed the best sulfate resistance in a sodium sulfate environment and the worst performance in a magnesium sulfate environment. Also, the normal 0.58 w/c ratio of 300 kg/m 3 cement content mix showed 1.5 times better performance than the 0.36 w/c ratio 450 kg/m 3 cement factor mix in magnesium sulfate environment. High-strength concrete showed three to four times better performance against chloride penetration compared to normal strength concrete. Use of 10 percent silica fume further improved resistance against chloride penetration.

The current design recommendations for concrete deep beams given in the ACI Code, Canadian Code, CEB-FIP Model Code, CIRIA Guide-2, etc., are based on research results on normal strength concrete. As such, these design recommendations may not be directly applicable to deep beams made of high-strength concrete. A summary of the authors' recent research on the shear behavior of deep beams made of high-strength concrete is presented. Experimental results on the ultimate shear strengths of single-span, continuous, and slender deep beams as affected by the strength of concrete, shear-span-to-depth ratio, and slenderness ratio, are compared to various design methods. It is found that the ACI method is overly conservative for all cases, the Canadian Code method is unconservative for higher strength concrete, the CEB-FIP method gives somewhat scattered predictions, and the CIRIA Guide-2 is slightly unconservative for all cases. A minor modification on the CIRIA Guide-2 method is shown to yield a reliable method for all the cases investigated.

Reports data from a comparative, long-term study of several blended cements. The study compared the performances of five different binder systems for strength and for properties related to durability. It was found that both ground granulated blast furnace slag (ggbs/slag) and silica fume (microsilica) were very efficient in improving durability and impermeability. The two materials combined with OPC in a triple blend showed better performance than either on its own, and in this combination, silica fume compensated for much of the delayed strength development in slag cement concretes. Paper gives a thorough summary of the results obtained during the first 30 months of the project.