Saddam M. Ahmed

Creating sustainable mortar containing recycled seashells is an innovative approach that can contribute to environmental conservation and reduce waste. The use of seashells as a partial replacement for traditional raw materials in mortar can have several benefits, including conservation of natural resources, waste reduction, and improved material properties. The current study uses Marsh Clam seashells after crushing the cleaned seashells into powder. Heated ( up to 600C°) and unheated seashells were considered in the experimental investigation. In both batches, a seashell powder (heated and unheated) was replaced with OPC cement in proportions of 6, 9 and 12% in the mixing process. XRD, SEM, EDS and mechanical tests were employed to determine the crystal structure and to provide a comprehensive understanding of the physical, chemical, and structural characteristics of the substance. The study concluded that the calcium carbonate (CaCO3) that is nature chemical form of seashells was turned to calcium oxide (CaO) during the heating process and the resulted product was highly reactive with water, improved microstructural properties of the concrete. It also promotes better particle packing, reduce porosity, and create a denser, more uniform concrete matrix and enhancing the overall performance of the material.

Nondestructive tests 'NDT' are increasingly becoming necessary tasks to develop accurate measurements without ‌causing ‌‌any ‌damage to ‌the tested elements‌. The outcome of the NDT is vital to determining the safety ‌and ‌‌reliability ‌composition of materials. This study aims to investigate the dependability of nondestructive tests using Schmidt Hammer and Destructive Core Tests in a fire-damaged area. More ‌than hundred ‌stations were considered in ‌the nondestructive inspection. ‌Destructive core test results were used to assess the NDT results in burned concrete elements. The results of the comparison, clearly demonstrated ‌the ability of both destructive and nondestructive ways‌ to capture the strength reductions in fired elements. The NDT test provided an optimistic and higher strength prediction (higher 35-67%) as compared to destructive tests. Greater optimism NDT results were significantly associated with elements that have been highly damaged by fire and the strength predictions efficiency were between 60-67%. The results showed deviations in the mechanical properties of predicted burned concrete strength, by both on-destructive and nondestructive ways that required strength calibration to the nondestructive test to ensure more reliable assessment. A strength degradation formula is also suggested and is under review.

Nondestructive tests 'NDT' are increasingly becoming necessary tasks to develop accurate measurements without ‎causing ‎‎any ‎damage to ‎the tested elements‎. The outcome of the NDT is vital to determining the safety ‎and ‎‎reliability ‎composition of materials. This study aims to investigate the dependability of nondestructive tests using Schmidt Hammer and Destructive Core Tests in a fire-damaged area. More ‎than hundred ‎stations were considered in ‎the nondestructive inspection. ‎Destructive core test results were used to assess the NDT results in burned concrete elements. The results of the comparison, clearly demonstrated ‎the ability of both destructive and nondestructive ways‎ to capture the strength reductions in fired elements. The NDT test provided an optimistic and higher strength prediction (higher 35-67%) as compared to destructive tests. Greater optimism NDT results were significantly associated with elements that have been highly damaged by fire and the strength predictions efficiency were between 60-67%. The results showed deviations in the mechanical properties of predicted burned concrete strength, by both on-destructive and nondestructive ways that required strength calibration to the nondestructive test to ensure more reliable assessment. A strength degradation formula is also suggested and is under review.

Recycling paper and cardboard wastes are becoming important to maintaining a green world. In 2018 manufacturing building materials and their constructions account for 39% of global emissions (13.5 billion tons of CO₂). This danger alarm requires immediate action towards seeking for alternatives like traditional materials that have less impact on the environment. Therefore, the current study suggests using new combinations to develop lightweight green building materials. The current research proposes to conduct experimental studies to examine the optimal method for customizing cardboard as a binder for ecofriendly building materials. 17 different mixes were considered in the experimental program; none of these mixes contained cement or consumed any kind of energy. The aim is to develop sustainable lightweight construction materials. Experimental strength results showed a higher strength (up to 7.5 MPa) for some developed substances 22% higher than the strength of traditional mud samples and simultaneously reduction in their weights (dry density 1600 to 1600 kg m⁻³) in between 13%–16% with superior outdoor durability performance. With these promising results and advantages, the current study can be considered as a primary step towards production of ecofriendly building materials.

In the present work, an experimental investigation into the seismic behaviour of identical beam–column subassemblies was conducted by testing four half-scale joint models: one without a slab and others with slabs of varying slab parameters. The slab–beam–column joints were tested under static displacement-controlled cyclic loading. Slab participation was evaluated using slab bar strain gauge data with respect to storey drift. Actual effective slab widths were much larger than the ones typically used in the design. A large effective slab width would result in large shears in both the joint and in the column that could result in premature shear failures.

The beam-column joint is a crucial zone in a reinforced concrete moment resisting frame. It is subjected to large forces during severe ground shaking, and its behaviour has a significant influence on the response of the structure. In the present study, two half-scaled cast-in-situ beam-column subassemblies (i) without slab and (ii) with slab, with reinforcement detailing as per ACI 318-63 (1963) provisions are constructed. The beam-column joints are comprehensively instrumented and tested under static displacement controlled cyclic loading. This paper explains the contribution of the floor slab, especially in “Tension flange” on the overall cyclic behaviour of the subassembly, and the experimental results of horizontal joint shear stress are discussed, and compared with the ACI 352R-02 provisions.