الفهرس 
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Abstract
Green concrete is defined as a concrete which uses waste material as at least one of its components, or its production process does not lead to environmental destruction, or it has high performance and life cycle sustainability. Advantages of green concrete issue stainability and climate change; green concrete is gaining popularity as an eco-friendlier alternative to traditional concrete. The production of green concrete encompasses different aspects of sustainability, including social, economic, and environmental.
The production of OPC has a huge environmental impact due to the released into the atmosphere. The production of 1 ton of cement contributes 1 ton of CO2 to the atmosphere, together with7% of greenhouse gases annually worldwide. (Methane, Nitrones oxides and Fluorine) Lately, an environmentally friendly concrete such as geopolymer concrete appeared to be an alternative for OPC.
Flat slabs systems are commonly used in multi-storey buildings because of saving in storey height and construction time. However, they frequently suffer from one of the major problems of flat slab is the punching shear flexure of slab column connection. This failure must be avoided. In the design of reinforced concrete flat slabs, the regions around the column always cause a critical analysis problem. Column inclines to punch through the flat slabs and footings because of the shear stresses. Due to greater uncertainty in forecasting shear failure, which is likely to occur suddenly with no advance warning of danger; therefore, shear failure, both beam and punching type considers more dangerous than flexure failure.
This research consists of two sections. The initial section, estimate mechanical properties of geopolymer concrete with different additives.as different steel fiber types, Nano metakaolin and Nano-silica on the mechanical properties (the compressive strength, splitting tensile strength and flexural strength) of ordinary Portland concrete (OPCC) and geopolymer concrete (GPC) mixes. To achieve this aim, different geopolymer concrete mixes were prepared. Firstly, with and without non material’s (nano silica and nano metakaolin) of 0, 2%, 4%, 6%, and 8% from ground granulated blast furnace slag (GGBFS) were used. Secondly, steel fiber (hooked end and crimped) content of (0, 0.5%, 1, and 1.5%) was used. Thirdly, optimum values of non material’s with the optimum values of steel fiber were used. Crimped and hooked-end steel fibers were utilized with an aspect ratio of 60 and a length of 30 mm. Geopolymer mixes were manufactured by using a constant percentage of alkaline activator to binder proportion equal to 0.45 with GGBFS cured at ambient conditions. For alkaline activator, sodium hydroxide molar (NaOH) and sodium hydroxide solution (NaOH) were used according to a proportion (Na2SiO3/NaOH) of 2.33. The results illustrated that using a mix composed of the optimum steel fibers (1% content) accompanied by an optimum percentage of 6% nano metakaolin or 4% nano silica demonstrated a significant enhancement in the mechanical properties of GPC specimens compared to all other mixtures. Besides, the impact of using nanomaterials individually was found to be predominant on compressive strength on GPC specimens especially with the usage of the optimum values. However, using nanomaterials individually compared to using the steel fibers individually was found to have approximately the same splitting tensile strength and flexural performance.
In the second section, Study the effect of punching shear on the behaviors of OPCC and GPC flat slab. 24 slabs were examined, including 12 flat slabs made of OPC concrete and the remaining 12 slabs made of Geopolymer concrete. Steel fiber volume percentage (Vf%) (0%, 1%, 1.5%, 2%). In this investigation, reinforced concrete slabs with a single bay were employed. This bay was 1000 mm × 1000 mm in size, with the slab thicknesses supposed to be (60 mm, 80 mm, and 100 mm), and the square column measurements assumed to be (100 x 100 x 300) mm. The results have shown a significant increase of the punching shear strength, ultimate load capacity, energy absorption capacity, Crack pattern, mode of failure and ductility of the slabs by addition of steel fibre in concrete were analyzed here in this study.
In numerical analysis, the finite element software program (ANSYS 2023 R2 STUDENT) was used to represent the reinforced slab-column connections to extend the parametric study to include cases that were not investigated experimentally.
Thirty concrete slab models, fifteen of which will be flat slabs made of OPC concrete and fifteen of which will be flat slabs built of Geopolymer concrete, will be evaluated for punching shear in this study. Concrete with a steel fiber volume percentage (Vf%) of 0%, 0.5%, 1%, 1.5% and 2%.
Finally, it is shown that the ultimate punching load capacity of slabs is increased when combining geopolymer concrete with steel fiber. The maximum punching load capacity of geopolymer concrete slabs reinforced by fibers was higher than the maximum load capacity of slabs reinforced with ordinary Portland cement (OPCC).
Keywords: Fibre Reinforced Geopolymer Concrete Slabs (FRGC), Punching Shear, Ultimate Punching Capacity (UPC), Steel Fibre, Corrugated Round Steel Fibre, Ordinary Portland Cement Concrete (OPCC).