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Behavior of prestressed fiber-reinforced steel-lined concrete slabs under projectile impact

Almusallam Tarek, Abbas Husain, Hodali Omar, Siddiqui Nadeem, Al-Salloum Yousef

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 1

art. no. e64, 2023

Recently, investigators have found that the application of prestressing, addition of fibers, and steel lining can improve concrete's overall performance, including its impact resistance. There is, however, no study in the available literature on the impact response of steel-lined post-tensioned fiber-reinforced concrete (PFRC). This study examines how steel-lined PFRC responds to projectile impact. The PFRC slabs with/without a steel lining on the rear face were tested against the impact of hemispherical-nosed projectiles at varied velocities using a gas-gun facility. The test results revealed that steel fiber volume increased the ballistic limit, reduced penetration and scabbing depths, and reduced ejected mass substantially from the back face. The use of steel lining on the back face caused a substantial increase in the ballistic limit and caused a significant reduction in the ejected mass. NDRC equations are modified to incorporate the effects of prestressing, steel fibers, and steel lining to predict penetration depth. Another empirical model is developed for ballistic limit prediction of the prestressed steel-lined fiber-reinforced concrete slab by incorporating the prestressing, steel fibers, and steel lining in the UKAEA formula. The models agreed well with the experimental results.

Development of metakaolin‑based geopolymer rubberized concrete: fresh and hardened properties

Alsaif Abdulaziz, Albidah Abdulrahman, Abadel Aref, Abbas Husain, Al-Salloum Yousef

Archives of Civil and Mechanical Engineering

2022

Vol. 22, no. 3

art. no. e144

During the past two decades, geopolymer concrete has been investigated as a sustainable alternative to Portland cement concrete, which is known to generate a huge amount of CO2 in the environment. This study focuses on the assessment of the fresh and hardened mechanical properties and durability of metakaolin (MK)-based geopolymer rubberized concrete. Crumb rubber was derived from discarded waste tires, another pollution source to the environment, and incorporated in concrete as fine aggregate replacement in ratios from 10 to 50% by volume. The performance of the MK-based geopolymer rubberized concrete is discussed based on its workability, air content, stress-strain behavior (including compressive strength and modulus of elasticity), flexural strength, dry unit weight and rapid chloride penetrability. The results show that the proposed sustainable concrete mixes achieve acceptable fresh and hardened mechanical and durability properties. The compressive strength when crumb rubber replaces fine aggregates in volumetric percentages between 10 and 40% are in the range of 28.7-39.7 MPa. Furthermore, the unit weight and modulus of elasticity of the MK-based geopolymer rubberized concrete mix with 40% rubber replacement are 14.9 GPa and 2134 kg/m3, respectively. This can promote a potentially large market for the MK-based geopolymer rubberized concrete products in applications where the priority is for decreasing self-weight and increasing flexibility rather than strength.