Civil Engineering and Architecture 9(5): 1434-1441, 2021 http://www.hrpub.org DOI: 10.13189/cea.2021.090516 Concrete Behaviour with Volcanic Tuff Inclusion Walid. Fouad Edris 1,2 , Safwat. Abdelkader 2 , Ahmed. H. E. Salama 1,3,* , Abd Al-Kader A. Al Sayed 4 1 Department of Civil Engineering, Hijjawi Faculty for Engineering Technology, Yarmouk University. P.O. Box 566, Irbid 21163, Jordan 2 Department of Civil Engineering, Giza High Institute of Engineering and Technology, Giza, Egypt 3 Department of Civil Engineering, Al-Azhar University, Nasr City 11884, Cairo, Egypt 4 Department of Civil Engineering, Higher Technological Institute, 10 th of Ramadan City, Egypt Received May 20, 2021; Revised June 21, 2021; Accepted July 25, 2021 Cite This Paper in the following Citation Styles (a): [1] Walid. Fouad Edris, Safwat. Abdelkader, Ahmed. H. E. Salama, Abd Al-Kader A. Al Sayed , "Concrete Behaviour with Volcanic Tuff Inclusion," Civil Engineering and Architecture, Vol. 9, No. 5, pp. 1434 - 1441, 2021. DOI: 10.13189/cea.2021.090516. (b): Walid. Fouad Edris, Safwat. Abdelkader, Ahmed. H. E. Salama, Abd Al-Kader A. Al Sayed (2021). Concrete Behaviour with Volcanic Tuff Inclusion. Civil Engineering and Architecture, 9(5), 1434 - 1441. DOI: 10.13189/cea.2021.090516. Copyright©2021 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract This study evaluates the effect of substituting cement by volcanic tuff on the workability, mechanical properties, and durability of concrete. Five mixtures were prepared with volcanic tuff ratios to cement of 0%, 5%, 10%, 15% and 20%. First, X-Ray Fluorescence (XRF) test for volcanic tuff was performed. Then, slump test was conducted for fresh concrete specimens. Moreover, tests for flexural strength, splitting tensile strength, elevated heat resistance, ultrasonic pulse velocity, and Scanning Electron Microscope (SEM) were performed at 28-days age of concrete specimens. Compressive strength, and absorption tests were conducted at 28, and 56-days ages of specimens. The study showed that slump, compressive strength, flexural strength, and splitting tensile strength were decreased with the increasing of volcanic tuff to cement replacement ratio at 28-days age. Additionally, the highest compressive strength and lowest water absorption for concrete were obtained at 56-days age of specimens and 10% volcanic tuff to cement replacement ratio. Keywords Volcanic Tuff, Compressive Strength, Natural Pozzolan, Concrete, Cementitious Material 1. Introduction Currently, the use of cement in concrete has negative environmental impacts due to the large number of carbon dioxide emissions during its manufacturing process. Meanwhile, cement is considered the most expensive ingredient in concrete because it consumes a large amount of energy during production which affecting the economic aspect of the concrete industry. Accordingly, it was necessary to search for materials that can be used as a supplementary of cement. These supplementary cementitious materials should be available, inexpensive, and can improve the properties of concrete. Different substitution materials will have different effects on the properties of the cement due to their chemical, physical and mineralogical characteristics [1–3]. Pozzolanic materials are widely used as supplementary cementitious materials in concrete. Pozzolanic materials can be classified to natural and artificial pozzolanic materials. Natural pozzolanic materials are materials such as zeolite, and volcanic tuff, while artificial pozzolanic materials are materials such as silica fume, fly ash, and metakaolin [4–6]. Volcanic tuff is one of the most pozzolanic materials which can be found as a natural material in Middle East countries (such as Egypt, Jordan, and Saudi Arabia). Jordan has available huge quantities of volcanic tuff (estimated as 800 million tons) [7]. Consequently, volcanic tuff was chosen to be used as a supplementary cementitious material in this research. The replacement of cement by pozzolanic materials could improve the mechanical properties of cement and concrete composites. Replacement dosages between 5 to 50% by weight of cement were commonly used [8–10].