Investigation on Mechanical and Durability Properties of Concrete Mixed with Silica Fume as Cementitious Material and Coal Bottom Ash as Fine Aggregate Replacement Material

Cement production produces a high amount of carbon dioxide, which has a negative impact on the environment. By utilizing waste products instead of cement, environmental degradation can be reduced. The current study was undertaken to study the mechanical and durability performance of concrete by replacing 7.5%, 10%, and 12.5% silica fume (SF) of cement weight. Additionally, coal bottom ash (CBA) was also substituted as fine aggregates with 10%, 20%, and 30%. Compressive strength and indirect tensile strength were the major parameters regarding mechanical properties, while corrosion analysis and sulfate attack were set for durability performance. Sixteen mixes were prepared including a control mix. Out of these, three mixes contained SF, three mixes contained CBA, and eight mixes contained both SF and CBA with 1:2:4 ratio at 0.5 w/b ratio. The results concluded that the addition of 12.5% SF and 30% CBA gives optimum compressive strength and tensile strength. Furthermore, using the SF and CBA reduces the workability of concrete. Furthermore, the use of these byproducts increased the durability in terms of corrosion and sulfate attack.

Standardization and application of external (in air) Particle Induced Gamma Emission (PIGE) method for rapid and non-destructive quantification of light elements at major to trace concentrations in coal, bottom ash and coke samples

Coal is an important energy source and its quality evaluation in terms of ash content and other element like B and F is a necessity. An external (in air) Particle...

A Comparative Study on the Thermal Conductivity of Concrete with Coal Bottom Ash under Different Drying Conditions

The utilization of coal bottom ash (CBA) and fly ash in concrete has become more common. For CBA concrete, curing conditions would influence the thermal properties of the concrete due to the high water absorption capacity of the CBA aggregate. In addition, CBA and fly ash contents in concrete affect the thermal properties of the concrete. Therefore, the effects of the drying conditions and the CBA and fly ash contents on the thermal conductivity of CBA concrete were investigated in this study. The thermal conductivity of concrete was measured under two different curing and drying conditions: oven-dried conditions and saturated surface-dry (SSD) conditions, with curing times of 28 and 91 days. The concrete mixtures also contained different levels of CBA and fly ash. Crushed sand in the concrete mixtures was replaced by CBA with replacement ratios of 25%, 50%, 75%, and 100% by volume. In addition, cement in the concrete mixture was substituted by fly ash with replacement ratios of 20 and 40% by volume. The thermal conductivity of concrete under the oven-dried conditions was much lower than that under the SSD conditions. Moreover, the thermal conductivity of the concrete decreased as the CBA content increased under both the oven-dried and SSD conditions. The material properties of the concrete, including unit weight, compressive strength, and ultrasonic velocity, were also measured in the study. Compared with the SSD conditions, the compressive strength, unit weight, and ultrasonic velocity of CBA concrete were considerably lower under the oven-dried conditions. Moreover, the relationships between the thermal conductivity and unit weight, compressive strength, and ultrasonic velocity were suggested.

Briquettes from Biomass Waste

This research made three kinds of briquettes from various biomass waste, including alaban wood charcoal and rubber seed shells mixed with coal bottom ash and coal fly ash. The purpose of the study was to obtain the characteristics and quality of briquette combustion. Making briquettes is by drying, grinding, and sifting raw materials then mixed with adhesive, printing and drying. Briquettes were made with variations in composition and pressure and the particle size of the material passing through the 50 and 250 mesh sieves. Briquettes produced from alaban wood charcoal and coal bottom ash, or fly ash, obtained more bottom ash or fly ash composition characteristics. The moisture content and calorific value would be lower while the ash content was higher. While the initial ignition time, the combustion duration is getting longer, but the burning rate would decrease. Briquettes made from rubber seed shells and coal bottom ash obtained variations in composition and pressure that affect the characteristics and quality of combustion. The higher the rubber seed shell composition and pressure, the lower the water and ash content, but the calorific value increased.