A STUDY ON EFFECT OF COAL BOTTOM ASH/BOILER SLAG ON STRENGTH AND DURABILITY PROPERTIES OF CONCRETE

Abstract

Each year, India generates almost 30 million metric tonnes of coal bottom ash/boiler slag (CBA). Communities in the area are put at risk due to the dumping of ash from adjacent thermal power facilities. CBA disposal issues may be effectively mitigated by its productive use.

This research is being done to determine how practical it would be to use CBA as natural fine aggregate (NFA) in construction projects. The compressive strength (CS) of both Concrete 'A' and Concrete 'B' was planned to be 38N/mm2 and 34N/mm2, respectively. CBA is used to substitute NFA in the two kinds of concrete at varying percentages (20, 30, 40, 50, 75, and 100). The freshness of concrete is tested for its workability. At 90 days of age, samples were tested for acid and sulphate resistance, as well as CS and cracking split tensile strengths (TS). CBA may be successfully used as a fine aggregate substitute in both types of concrete, as shown by the test results. CBA concrete mixes exhibited reduced CS at 7 days. In comparison to the control concrete (CC) mixes' 38.20 and 34.0 N/mm2, the CS of the CBA concrete ranged from 35.0 to 37.5   N/mm2 for Mixs 'A' concrete and from 26.7 to 32.2 N/mm2 for mixes 'B' concete after 28 days. CBA concrete combinations had a greater rise in   CS   over   time   than normal concrete mixtures. After 90 days, the CS of both the CBA concrete combination and the CC mixture (mixtures 'A' and 'B') are quite close to one another.

Concrete mixture 'A' had a TS ranging from 2.72 to 2.96N/mm2 after 28 days, whereas Concrete mixture 'B' had a strength ranging from 2.16 to 2.52N/mm2. Both Concrete 'A' and 'B,' made from the control mixture, had TS of 2.67N/mm2 after 28 days. CBA concrete mixes 'A' and 'B' had TS equivalent to or greater than the corresponding CC mixtures after 90 days. Under external sulphate treatment, both grades of CBA concrete expanded more than standard concrete, although the overall stresses were far below the 0.1 percent threshold at which CS begins to decrease. CS after 28 days showed no signs of deterioration