Shiw S. Singh

Bio: Shiw S. Singh is an academic researcher from University of Wisconsin–Milwaukee. The author has contributed to research in topics: Fly ash & Compressive strength. The author has an hindex of 19, co-authored 41 publications receiving 1215 citations.

Mechanical properties and durability of concrete made with blended fly ash

Abstract: This study focused on evaluating the effects of blended fly ash on mechanical properties and durability of concrete. In this investigation two reference mixtures were used. One was a mixture without fly ash, and the other contained 35% ASTM Class C fly ash. Additional mixtures were composed of three blends of ASTM Class C and Class F fly ash while maintaining a total fly ash content of 40% of the total cementitious materials. Mechanical properties such as compressive strength, tensile strength, flexural strength, and modulus of elasticity were determined. Durability related properties determined were drying shrinkage, abrasion resistance, salt scaling resistance, and electrical prediction of chloride ion penetration. The results showed that blending of Class C fly ash with Class F fly ash showed either comparable or better results than either the reference mixture without fly ash or the unblended Class C fly ash. Blending of fly ash, therefore, leads to comparable or better quality and reduced cost, attributed to the use of Class F versus Class C fly ash in concrete.

Abrasion resistance of high-strength concrete made with class c fly ash

Abstract: This work was performed to evaluate the abrasion resistance of concrete proportioned to have five levels of cement replacements (15, 30, 40, 50, and 70 percent) with one source of Class C fly ash. A reference concrete without fly ash was proportioned to have a 28-day compressive strength of 41 MPa. Concrete specimens were subjected to abrasion according to the American Society for Testing and Materials (ASTM) C 944 test method. In this work, all concretes made with and without fly ash passed the abrasion resistance requirements per ASTM C 779, Procedure C. Depth of wear values produced by the ASTM C 944 test were quite low for the strength levels tested in this work. An accelerated test method was developed and used to evaluate the abrasion resistance of high-strength concrete. This method used grinding wheels with smaller washers, and a standard "Ottawa sand" was applied to the surface being abraded at intervals of 1 minute. Accelerated test results revealed that the abrasion resistance of concrete having cement replacement up to 30 percent was comparable to the reference concrete without fly ash. Beyond 30 percent cement replacement, fly ash concrete displayed slightly lower resistance to abrasion relative to non-fly ash concrete.

Properties of Field Manufactured Cast-Concrete Products Utilizing Recycled Materials

Abstract: This investigation was performed to develop technology for manufacturing cast-concrete products using Class F fly ash, coal-combustion bottom ash, and used foundry sand. A total of 18 mixture proportions with and without the by-products was developed for manufacture of bricks, blocks, and paving stones. Replacement rates, by mass, for sand with either bottom ash or used foundry sand were 25 and 35%. Replacement rates, by mass, for portland cement with fly ash were 25 and 35% for bricks and blocks, and 15 and 25% for paving stones. Analysis of test data revealed that bricks with up to 25% replacement of cement and blocks with up to 25% replacement of cement and sand with recycled materials are suitable for use in both cold and warm climates. Other bricks and blocks were appropriate for building interior walls in cold regions and both interior and exterior walls in warm regions. Paving stones with 15% replacement of cement with fly ash showed higher strength, freezing and thawing resistance, and abrasion resistance than the control specimens.