الملخص: تعاقب على المدينة القديمة عدة حضارات وتركت بصمة تمثلت في المباني القديمة، والتي يتطلب المحافظة عليها وصيانتها وترميمها لتبقى كثروة أثرية، ولكن من الملاحظ تدهور هذه المباني نتيجة العوامل الجوية وتدخل الإنسان مع عدم الصيانة لبعضها وصيانة البعض الأخر بطرق خاطئة كاستخدام مواد الاسمنت أو الطوب بدل من الأحجار والجير والطين المستخدم قديما ، بالإضافة إلي استيراد مواد الترميم من الخارج مما دفع بالباحثين لمحاولة إيجاد مواد محلية بديلة تكون مناسبة للترميم، ومما شجع علي ذلك توفر مادتي الجير والطين بكميات كبيرة داخل ليبيا. لذلك انطلقت هذه الدراسة بحرق عينتين من الطين تمثلت في طين يفرن وسبها لتحويلها إلى مواد بوزولانية تتفاعل مع الجير من خلال تحضير عينات من المونة المحتوية على الجير والرمل مع نسب من البوزولان تراوحت من 0% إلى 50% من وزن الرمل الطبيعي لتحديد مقاومة الضغط، وأظهرت النتائج المتحصل عليها قيم مشجعة وفتحت بابا للدراسات المستقبلية بهذا المجال، وأعطت أملاً للحصول على مواد الترميم من الخامات المحلية والاستغناء عن الاستيراد arabic 100 English 0
هيفاء علي رجب ابوحليقة(11-2020)

Download PDF Research Article - Civil EngineeringPublished: 31 July 2019Investigation on Mode I Fracture Behavior of Hybrid Fiber-Reinforced Geopolymer CompositesNeha P. Asrani, G. Murali, […]K. Karthikeyan  Arabian Journal for Science and Engineering volume 44, pages8545–8555(2019)Cite this article 225 Accesses 4 Citations Metricsdetails Abstract Recent reports in the literature have shown that fiber-reinforced geopolymer composites (FRGC) made with monofibers exhibit a significant enhancement in fracture energy. However, many aspects of the fracture performance of hybrid fiber-reinforced geopolymer composites (HFRGC) remain largely unexploited, and these are predominant for the structures. For the first time, the mode I fracture energy of HFRGC is investigated. The mode I behavior was assessed using pre-notched beams in accordance with the RILEM three-point bending test. Five different HFRGC mixtures were prepared using three fiber types: steel, polypropylene and glass (SF, PF and GF). The parameters of the pre-notched beam in flexure tested in this study were the first crack and peak load, crack mouth opening displacement at the first crack load and peak load, equivalent tensile strength, post-peak slope, reinforcing index, residual tensile strength and fracture energy. The results reveal that there is a positive interaction amidst the fibers in geopolymer composites that leads to an enhancement in the mode I fracture energy compared to the reference specimen. This study probes the influence of novel HFRGC while producing high-quality concrete, which can then be leveraged for sustainable infrastructure and various civil engineering works. arabic 15 English 79
Hakim Salem Abdelgader Abdelgader (7-2019)

Cement is still the most popular binder used in buildings construction. The volume of cement production in the world since 2013 has remained at the level of approximately 4.1 billion tons. The cement production process is energy intensive and is the world’s leading emitter of carbon dioxide. Therefore, the main activities cement plants are aimed at introducing technologies changes in production of clinkier (Edwards, 2019).The construction industry is responsible for the majority of CO2 emissions to the atmosphere: the industry emits 30% of total CO2, building emits 28%, transportation is responsible for 22% of CO2, the production of building materials causes 11% of CO2 emissions, including the cement industry is responsible for around 7% of emissions CO2. Other industries are responsible for around 9% of CO2 emissions to the atmosphere (Amran et al., 2020). The process of burning raw materials for the production of clinker is the most important stage of the entire cement production process (Mikulˇci´c et al., 2013; Andrew, 2019). Cement kiln dust (CKD) is waste generated during the production of clinker. The dust collected in the dust collectors is partly reused in the production process and some is stored. The storage method is not preferred due to its operations negative environmental impact. If the dust contains alkalis, chlorides, sulphates, or heavy metals, they cannot be recycled. Generally cement plants strive to reduce the formation of dust. About 1.5 tons of raw materials are used to produce 1 ton of clinker. After the extraction, grinding, and homogenization of rawmaterials, the process of calcination of calcium carbonate takes place.
Hakim S. Abdelgader(1-2022)