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This investigation was conducted to establish database for manufacturing of concrete masonry products incorporating high volumes of ASTM Class F fly ash. A total of 15 mixture proportions for bricks, blocks, and paving stones, including reference mixture for each type of masonry product, was proportioned. The fly ash content was varied from 20 to 50% for brick and block mixtures, and from 15 to 30% for paving stone mixtures All masonry products were tested for compressive strength, density, absorption, freezing and thawing resistance, drying shrinkage, and abrasion resistance. Test results indicated that bricks and blocks with up to 30% fly ash are suitable for use in both cold and warm climates. Other brick and block mixtures containing up to 50% fly ash were appropriate for building interior walls in cold regions and both interior and exterior walls in warm regions. None of the paving stone mixtures, including the control mixture, strictly conformed to all ASTM requirements. However, all the paving stone mixtures with and without fly ash are suitable for normal construction applications.

The purpose of this research was to study the penetrating characteristics of chloride ions into fly ash concrete and the corrosion of steel reinforcement in concrete, where some parts of fine and coarse aggregates were replaced by fly ash . Several tests such as compressive strength test, chloride penetration test and corrosion diagnosis of steel reinforcement in concrete were performed. Through these tests, the physical properties and durability of fly ash concrete against aggressive environments have been studied.

Superior durability of fly ash concretes have been very well established by many research works throughout the world. However, the decision to use the fly ash concrete or not and also the fly ash content in the concrete is based on the cost of the concrete in most of the cases, if not all. Thus a methodology has been developed to estimate the optimum fly ash content for the lowest cost and maximum durability of the concrete. Concrete of different fly ash content were prepared and their costs were calculated. Durability properties of some of the concrete were determined by experimental measurement of their relative service life. The type of environment was also considered. Optimum fly ash content was determined based on cost, durability of the concrete, and the type of environment. The price structure of concrete-making materials in Australia was used as an example in the calculation of optimum fly ash content for the lowest price. It is expected that the price structure found in other countries would be different and accordingly the optimum fly ash content will be also different. However the methodology has been presented and this methodology can be used to calculate the optimum fly ash content for any price structure. This methodology provides scientific way of estimating the fly ash content which would give the lowest cost for an environment.

This paper reports results from ASTM C 1012 (sulfate resistance) tests on combinations of fly ash and silica fume with portland cements of varying C3A content. Tests on different types of fly ashes confirm previous findings regarding the effects of fly ash composition. Low-calcium ashes invariably improve the sulfate resistance of mortars made with high-C3A portland cement and generally meet the criteria for high-sulfate resistance provided a sufficient level of replacement is used (e.g. 2 20 to 25% fly ash by mass of cementitious material). Moderate-calcium ashes were generally less effective, but could still be used to produce blended cements of moderate to high sulfate resistance when combined with a high-C3A cement at replacement levels of 20%. High-calcium (i.e. CaO > 20%) fly ashes showed highly variable performance and in many cases replacement levels of 20% to 40% actually lead to increased expansion when compared with high-C3A cement used on its own. Results for a classified ultra fine fly ash indicate improved performance with relatively low levels of ash (e.g. 8 to 16%) producing a high level of resistance when combined with high-C3A cement. It was found that mortars containing moderate to high levels of high-calcium fly ash could be produced to meet the criteria of high-sulfate resistance by using either portland cements of lower C3A content or ternary cement blends containing relatively low levels of silica fume (e.g. 3 to 6% by mass of total cementitious material). However, in view of the highly variable performance observed for mortars containing high-calcium fly ash, the need to test individual combinations of materials is stressed.

Offshore platforms serve as artificial bases, supporting drilling and production facilities above the elevation of waves. They can be damaged due to wave induced fatigue in synergy with chloride-induced corrosion. These structures are constructed mainly using cylindrical steel tubular members and the joints, formed at the intersection of members, are most vulnerable to fatigue. An innovative repair technique, which has made use of fly ash and epoxy based high performance grout (HPG) especially developed for this purpose and ferrocement jackets, was proposed in this investigation to rehabilitate fatigue damaged tubular joints. While the average compressive strength of the grout was 85 MPa (12.32 ksi), the average tensile strength was 52 MPa (7.54 ksi). The bond strength of the HPG was almost three times greater than the conventional cement grout. As the specific property, the bond is very high, and achieved without any effort, the term High Performance Grout’ has been used in this paper to disguish it from the conventional technique. The paper presents in detail the necessity and development of the fly ash and epoxy based HPG, the method of repairing the fatigue damaged tubular joint, and the testing of the repaired joint to check the efficacy of the proposed innovative technique.