Use of Waste Paper Sludge Ash as Partial Replacement of Cement in Mortar
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Date
2022-06
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Publisher
Addis Ababa University
Abstract
Various industrial wastes were employed as supplemental cementitious materials to save
the environment from filling with non-biodegradable wastes and to limit the
consumption of existing limestone. Waste paper sludge makes up a significant
component of the numerous materials produced as byproducts in the paper industry. The
overall goal of this research is to determine the suitability of waste paper sludge ash as a
partial cement replacement material by conducting compressive strength and reactivity
tests while substituting cement in various quantities.
The end-by-product of the paper manufacturing industry is paper sludge, which is a wet
gray waste mud. This paper sludge is turned into ash and utilized as a partial cement
replacement. This research is entirely based on the use of waste paper sludge ash
(WPSA) as a cement replacement in mortar production. WPSA amounts of 0, 5, 10, 15,
20, 25, and 30% by volume of cement are used to make the mortar mix.
At the ages of 7, 28, and 56 days after curing under ambient conditions, the compressive
strength of mortar cube specimens was measured. The results suggest that increasing the
replacement level up to a certain level increases the strength of mortar cubes
incorporating waste paper sludge ash (WPSA). In terms of compressive strength, 15
percent replacement yielded the optimum results.
WPSA reactivity was assessed using a variety of techniques. This was accomplished by
assessing the reactivity of WPSA using a modified Chappelle test, estimating the amount
of bound water, and characterization of pastes using XRD analysis was done for a
sample at the optimum replacement level, i.e. 15%. The strength development was also
compared to the test results.
On day 7, reference sample had a bound water content of 4.18%, whereas blended
sample had a bound water level of 5.20%. WPSA has a reactivity of -1244.89 mg
Ca(OH)
2
per gram of WPSA. These findings suggest that the increase in compressive
strength is entirely due to the filler effect.
Description
Keywords
Waste Paper Sludge Ash, Mortar, Compressive strength, Reactivity