An Examination and Investigation Compressive Strength the Use of Waste Paper Sludge Ash and Rice Husk Ash as Cement Substitutes in Concrete . IJIREM [Internet]. 2023 Jun. 30 [cited 2025 Aug. 5];10(3):60-6. Available from: https://www.journals.acspublisher.com/index.php/ijirem/article/view/10218