International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 10 Issue: 06 | Jun 2023 www.irjet.net p-ISSN: 2395-0072 © 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 485 Evolution of the Physico-Mechanical Properties of Calcined Clay Cement from Different Sources of Kaolin Clay Aya R. Abdelfattah 1 , Abdelrahman Ragab 2 , Shaimaa Younis 2 , Magdy Elymany 1 1 MSc. Student, Civil Engineering Department, Faculty of Engineering, Fayoum University, Fayoum 63514, Egypt 2 Assistant Professor of Chemistry, Structural and Civil Engineering Department, Future Institute for Engineering, Fayoum, Egypt 3 Assistant Professor, Structural and Civil Engineering Department, Future Institute for Engineering, Fayoum, Egypt 4 Professor, Civil Engineering Department, Faculty of Engineering, Fayoum University, Fayoum 63514, Egypt ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - The development of binders based on limestone and calcined clays appears to be a promising way to increase the substitution of clinker. Their production is likely to remain limited if highly kaolinitic clays are required, but calcined clays with low metakaolin content are less reactive in a binder, as shown in many previous studies. This study focused on the differences, regarding hydration degree and products, between several binders containing two types of calcined clay and limestone filler. Two calcined clays were studied, coming from two very different raw clays. The first calcined clay contained more metakaolin than the second one. In this article, we produced the LC3 from two clays. The production of LC3 used 10, 15, 22.5, and 30% of calcined clay, 10 % of limestone filler, and 5% gypsum. This was also studied by using one type of each calcined clay individually. Binary binders showed strong differences between the two calcined clays. However, this work showed significant pozzolanic activity and synergy between calcined clay and limestone filler in the binder. This observation was made even for the composite calcined clay with minor metakaolinite content. From this comprehensive study on hydration, it can be concluded that calcined clay with low metakaolin content is likely to result in the same degree of hydration and products over the long term as high metakaolin calcined clay in a binary system, The LC3 formed from CC Zafarana and CC of Sinai was better than OPC, especially in the durability. cement pastes were investigated by the determination of water of consistency (W/C, %), setting times (STs), and compressive strength (CS). Some selected cement pastes were identified using XRD, TG and DTA techniques to show the hydration products with curing time. Key Words: Limestone calcined clay cement (LC3), CC=MK, Clinker partial replacement, Environmental Impact, Compressive strength, Microstructure. 1.INTRODUCTION In recent years, the world’s attitude in all fields has changed to go green. Due to the recent high records of the carbon footprint, many industries have turned to green manufacturing or processing. One of the most affecting industries on air pollution is cement production. This industry participates with large scale in the CO2 emissions as recorded around 6% of the global warming causes [1–5]. The cement production waste not only emits many harmful substances that can harm the human’s respiratory system, such as slag, ashes, cement dust, marble dust, etc.…, but also, they have a very high disposal cost [6]. Moreover, no matter how important cement is in our world, this production consumes an extreme amount of energy [7]. As a result, the cement industry stakeholders initiated new approaches to eliminate the waste from the beginning like replacing the cement with some sustainable alternatives with green impact on the environment; however, these replacement alternatives showed undesired results of the mechanical strengths of the cement [4]. Another opinion states that the cement industry wastes themselves can be recycled and result in higher superior mechanical properties and structure life, in this work [2], cement kiln dust and fly ash are reused to optimize the Portland cement. Many researches address the full or partial replacement of cement because of the previously mentioned reasons [8–17]. Therefore, Researchers introduced new ternary cementitious system called limestone calcined clay cement (LC3) that is a combination of ordinary Portland cement (OPC), limestone and calcined clay extracted from various regions around the world such as China [18,19], Brazil [17,20], North America, South Asia [21], Cuba [22] and Argentina [23]. This attracted the researchers’ interest to study the physico-mechanical properties of the new (LC3) concrete mixtures in order to present a sufficient final product that competes with the OPC mixtures. It is found that when the clay is calcined, metakaolin is formed that in turn react with calcium hydroxide producing C-A-S-H and aluminate hydrates. Then, the reaction between the alumina and the limestone produces carbo-aluminate hydrates. Eventually, all these reactions fill the porous spaces in the structure that lead to the improvement of the physico- mechanical properties of the cement [24–26]. Huang et al. [18] studied the development of LC3 paste that includes a calcined clay from Maoming, China. The study showed that early strengths of LC3 (before 7 days) tends to be lower than the OPC concrete, however, late strengths show remarkable strength increase compared to OPC, especially the flexural and splitting tensile strengths, due to the secondary reaction of the amorphas silica and alumina.