Advanced Modeling in Civil Engineering
Experimental Investigation of the Compressive Strength of Concrete Containing Phosphorus Slag as a Partial Replacement for Natural Sand
Document Type : Original Article
Authors
1 Master's student Civil Engineering Dept., Faculty of Engineering, Ahlul Bayt International University, Tehran, Iran.
2 Assistant Professor Civil Engineering Dept., Faculty of Engineering, Ahlul Bayt International University, Tehran, Iran.
Abstract
Phosphorus furnace slag, a by-product of the phosphorus production industry, is generally regarded as a waste material. In this study, the effect of using phosphorus slag as a partial replacement for natural sand on the compressive strength and workability of concrete was investigated. For this purpose, concrete mixtures incorporating various replacement levels of phosphorus slag (0, 5, 7.5, 10, 12.5, 15, 20, 30, 40, 50, and 60 percent by weight of sand) were produced, and compressive strength tests at ages 7, 14, and 28 days as well as slump tests were performed in accordance with ASTM C39 and ASTM C143 standards. The results indicated that incorporating limited amounts of phosphorus slag led to a significant increase in compressive strength and an improvement in the microstructure of the concrete. At 28 days, the specimen containing 7.5% phosphorus slag (PS-7.5) exhibited the highest compressive strength, reaching 28.32 MPa, which represents an increase of approximately 6.3% compared to the control concrete (26.62 MPa). Conversely, when the replacement percentage exceeded 20%, the compressive strength showed a decreasing trend. The slump test results similarly demonstrated a continuous increase in the workability of fresh concrete with increasing phosphorus slag content; the slump increased from 40 mm in the control specimen to 70 mm in the mixture containing 60% slag. Overall, the findings revealed that replacing approximately 7.5% of natural sand with phosphorus slag provides a desirable balance between compressive strength, fresh concrete workability, and environmental sustainability, and this range may therefore be considered optimal for producing structural concrete. This study is the first to employ phosphorus slag as a replacement for natural sand.
Keywords
Main Subjects
)