“An Examination and Investigation Compressive Strength the Use of Waste Paper Sludge Ash and Rice Husk Ash As Cement Substitutes in Concrete ”. International Journal of Innovative Research in Engineering & Management 10, no. 3 (June 30, 2023): 60–66. Accessed August 5, 2025. https://www.journals.acspublisher.com/index.php/ijirem/article/view/10218.