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Gypsumless Portland cements (GPC) are inorganic binders, which may be described aas system of: ground Portland clinker (specific surface of 400-500 m2/kg - Blaine), a surface-active agent with hydroxyl groups and a hydrolyzable alkali metal salt (carbonate, bicarbonate, silicate). New cements, developed in recent years, are able to reach both higher strengths and fracture toughness than ordinary Portland cement (1,2,3). New developments in the making of very strong cements have resulted from modifying cement compositions and manipulating the microstructures (4).

In High-Strength Concrete in general high-quality aggregate is used. This aggregate has a high compressive strength and often a high modulus of elasticity. This high modulus of elasticity of the aggregate strongly influences the deformation behaviour of high-strength concrete. Results show that there is a direct and linear relationship between the shrinkage value and the modulus of elasticity of the concrete. The highest modulus of elasticity of concrete was 85 GPa. The compressive strength at the age of 28 days was in the range from 102 to 182 MPa. A design aid is given to show the interrelation between modulus of elasticity and shrinkage strain of the concrete on one side and modulus of elasticity of the aggregate, modulus of elasticity of the matrix and matrix content on the other side.

This paper describes the characteristics of a super low-heat cement mixing the ternary components of cement, blast-furnace slag, and nace slag cement modifying portland blast-furnace slag cement into a low-heat type. The results of mass concrete model experiments conducted using these cement are also reported. The super low-heat cement used in furnace slag: fly ash at ratios of 23:50:27. The low-heat blast-furnace slag cement was a 60% mixture of blast-furnace slag in normal portland cement. In the experiments concerning characteristics of concrete, concretes using super low-heat cement or low-heat blast-furnace portland cement or portland blast-furnace slag cement Class B. Mass concrete model experiments were compared for the cases of using super low-heat cement, and portland blast-furnace slag cement Class B. According to the test results, in case of unit cement content of 300 kg/m2, the adiabatic temperature rise of concrete using super low-heat cement is approximately 15°C lower than the moderate heat portland cement. That of concrete using low-heat blast-furnace slag cement is approximately 5°C lower than portland blast-furnace slag cement Class B. Mass concrete model experiments show that the strength gain of super low-heat cement concrete is higher than that of conventional low-heat cement concrete, and this cement is effective in control of thermal cracking because of exceedingly low temperature rise.

The Akashi Kaikyo Bridge will be the world's longest suspension bridge, with a center span of 1990 m. The anchorage of this bridge at the Honshu side has its bearing layer at a depth of 60 m, and will be constructed as a concrete foundation surrounded by an underground wall at a depth of 75 m. This underground wall is composed of 46 slender reinforced concrete panels having a cross section of 2.2 x 8.5 m (preceding panels) and 2.2 x 3.2 m (following panels). Concrete is to be placed into slurry through tremies. It must have a high fluidity, low segregation, high strength, and low-heat generation. Therefore, a high-strength low-heat- generating concrete using a ternary-blended cement containing large amounts of blast furnace slag, fly ash, and superplasticizer was used. The results of tests on basic properties such as workability, strength, and heat generation of high-strength concrete using ternary-blended cement with a large amount of blast furnace slag and fly ash; test results of tests performed on experimental models; and results of actual work are described.

Various researchers have reported that the sulfate resistance of portland blast-furnace slag cements was reduced when the slag contained a high alumina content. Much of this testing has used much higher water-cement ratios for the test specimens than are normally used in construction. In this study, the mixtures have been modified to assess mortars additionally at lower water-cement ratios. The test program used the German "Flat-Prism" test to assess blends of cement and various combinations of two slags: one slag of low alumina content, and the other slag with a higher alumina content. Results of expansion testing up to an age of 4 years are reported and indicate that when used at the replacement levels and water-cement ratios specified in current U.K. standards and codes of practice, both slags can provide resistance to sulfate expansion. At higher water-cement ratios and lower slag replacement levels, expansion does occur. Commercial blends of the two slags, when used to optimize other properties (e.g., strength), would not compromise the sulfate resistance properties. The greatest sulfate resistance, as represented by the lowest expansion, was not provided by the slag with the lowest alumina content, but by a composite slag sample with an alumina level of about 13 percent.