Abed, FaridYehia, SherifKhalil, Khalid Hesham2025-03-252025-03-252024-1135.232-2024.70https://hdl.handle.net/11073/25950A Master of Science thesis in Civil Engineering by Khalid Hesham Khalil entitled, “Effect of Blended Lightweight and Normal Weight Aggregates on The Shear Capacity of Concrete Beams”, submitted in November 2024. Thesis advisor is Dr. Farid Abed and thesis co-advisor is Dr. Sherif Yehia. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).This thesis investigates the influence of internal curing using lightweight aggregate (LWA) on the shear capacity, shrinkage, and cracking resistance of concrete beams compared to conventionally cured mixes. Internal curing, achieved by incorporating pre-saturated LWA, provides an internal moisture reservoir that enhances hydration, particularly in low-water mixes, mitigating shrinkage and improving structural performance. The concrete mix included Portland cement (SG 3.15), Pumice 4-8mm as LWA from Turkey (SG 1.45), dune sand (SG 2.61), crushed sand (SG 2.61), normal-weight aggregates of 10mm and 20mm (SG 2.7), GGBS (SG 2.9), and silica fume (SG 2.2). The experimental program evaluated mechanical properties such as modulus of rupture, tensile strength, and compressive strength. Six reinforced concrete beams were tested under four-point loading without shear reinforcement. The three concrete mixes were: (1) "CC," cured conventionally, (2) "ICC," combining internal and conventional curing, and (3) "IC," using LWA solely for internal curing. Beams were subjected to increasing loads to observe cracking and shear capacity, while shrinkage and creep tests evaluated long-term stability. Results showed internal curing significantly improved structural performance. The ICC mix exhibited a 43.45% increase in shear capacity over CC, while IC showed an 11.52% increase. Shrinkage tests showed reduced microstrain in internally cured samples, confirming better volumetric stability. Creep tests revealed reduced long-term deformation, enhancing durability. This study highlights internal curing with LWA as an effective method to improve concrete performance, particularly in thick or sealed sections where external curing is less effective. However, proper LWA preparation is crucial to ensure sufficient moisture without compromising workability. These findings establish internal curing as a viable approach to enhancing shear capacity, reducing shrinkage, and improving durability for demanding structural applications.en-USLightweight aggregateBlended concreteShear behaviorInternal curing agentThesis