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Introduction/purpose: The consumption of natural sand in Algeria is high due to its extensive use in mortar, while sediments and rubber waste pose significant environmental and societal challenges. This study investigates the effects of incorporating rubber waste content in mortars mixed with crushed sand and sediment. The primary goal is to valorize crushed sand particles through physical and mechanical tests, evaluating their potential as an alternative to natural sand in mortar mixtures.
Methods: Experimental work was carried out to study the impact of partially and fully replacing sediments with crushed sand particles in mortar mixes. Mortar mixtures were prepared using different sediment-to-crushed sand ratios (10%, 25%, 35%, 50%, and 100%) to observe their influence on physical and mechanical properties. Additionally, the effects of adding 2%, 4%, and 6% granulated rubber to the optimal mortar were analyzed. Various tests, including those tsting compressive strength, flexural strength, and ultrasonic pulse velocity, were performed to evaluate the performance of the mixtures.
Results: The results indicated that replacing sediment with crushed sand improved the strength properties of mortar, particularly due to better particle packing. The mortar containing 65 wt% sediments and 35 wt% crushed sand showed properties similar to the reference mortar. The addition of rubber waste increased compressibility but enhanced mechanical properties when used in moderation. Ultrasonic pulse velocity decreased with higher crushed sand content, and the porosity of the mixtures was reduced.
Conclusions: Crushed sand and sediment particles are effective fillers for mortar, ensuring good performance and improved strength. The efficiency of these materials depends on their morphology and genesis. The study demonstrates that crushed sand can be a viable alternative to natural sand, and rubber waste can be used as a reinforcing material in mortar, though its proportions should be carefully controlled to avoid negative effects on mechanical properties.
Introduction/purpose: The use of supplementary cementitious materials (SCM) in construction has gained popularity due to their ability to improve the mechanical properties and environmental sustainability of concrete. This study aimed to investigate the potential of utilizing waste materials, specifically marble powder (MP) and dam sediment (DS), as partial replacements for cement in self-compacting concrete (SCC). The primary objectives were to recycle these waste materials and assess the durability and strength of SCC exposed to aggressive chemical environments.
Methods: In this study, cement was partially replaced with 40% MP, 40% DS, and a combination of 20% MP and 20% DS. The performance of such concrete was evaluated through compressive strength tests conducted for 28 days. Durability was assessed by exposing the concrete to chemical attacks from hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and sodium sulfate (Na₂SO₄) solutions. Mass loss due to these chemical attacks was also measured.
Results: The concrete incorporating MP demonstrated compressive strengths similar to that of the control concrete, achieving 37.61 MPa at 28 days. The concrete with DS exhibited lower strength (31.81 MPa) and showed higher resistance to HCl (ML = 38.78%) compared to the MP concrete (ML = 40.74%). Additionally, all concrete samples exhibited good resistance to sulfuric acid due to the formation of expansive ettringite which protected the concrete from further degradation.
Conclusions: The results indicated that both marble powder and dam sediment are viable supplementary materials for improving the mechanical properties and durability of SCC. The concrete with marble powder showed superior strength, while dam sediment contributed to enhanced acid resistance. The combination of these materials offers a sustainable solution for concrete exposed to aggressive environments.