Available online at www.CivileJournal.org Civil Engineering Journal (E-ISSN: 2476-3055; ISSN: 2676-6957) Vol. 7, No. 01, January, 2021 24 Properties of High-Performance Concretes made of Black Sand at High Temperature Khaled A. Eltawil 1* , Ahmed M. Tahwia 2 , Mohamed G. Mahdy 3 , Ahmed H. Abdelraheem 2 1 Ph.D. Candidate, Structural Engineering Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt. 2 Professor, Structural Engineering Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt. 3 Professor and Vice-dean for Students and Education Affairs, Faculty of Engineering, Mansoura University, Mansoura, Egypt. Received 01 October 2020; Revised 26 November 2020; Accepted 12 December 2020; Published 01 January 2021 Abstract To modify High-Performance Concrete (HPC) fireproofing properties, Black Sand (BS) was partially substituted as fine aggregate at various levels. This study aims at evaluating the BS reliability in improving HPC durability properties for various construction applications based on its unique heavy minerals. To achieve this, five HPC series blends were setup to substitute fine aggregate independently with BS. Substitution percentages ranged from 15 to 100% with consistent supplementary cementing materials (SCMs) proportion for each gathering. Tests were performed to assess compressive strength before and after fire exposure under various temperatures of 250, 500, and 750 °C at different curing age. Generally, blending FA with BS was better than using SF with BS. Utilizing BS in the range of 15 to 60% as fine aggregate with 10% FA improves HPC fire-insulating properties. Besides, Z1 SEM analysis observed homogenously and compacted HPC microstructure at 250 and 500 °C. Keywords: High-Performance Concrete; Black Sand; SEM; Fly Ash; Silica Fume; Fireproofing Properties. 1. Introduction For several years, scientists have looked all over to solve fire concrete structure issues. The fire has an extremely significant effect on the protection of the concrete structure and fire losses cannot be overlooked, particularly for the concrete structures in coastal areas, because of the durability of concrete structures [1]. For example, nuclear power plants (NPPs) concrete faced high temperature and sulfate chloride attack. The high temperature of over 300 °C deteriorated concrete due to cracks that began to occur in the microstructure. Several new strategies are proposed to improve concrete fireproofing properties such as using mineral admixture. Concrete technology manufacturing improves and presents new advanced concrete that can achieve specified performance for the given arrangement of materials, utilization, monetary, service life and durability known High-Performance Concrete (HPC). The HPC concept has unquestionably improved with time. HPC is utilized in various large-scale concrete construction fields needed high strength, flowability, durability, least porousness and different necessities that are unmistakable as demonstrated by use. It rejoins a particular blend of performance and consistency necessities, which * Corresponding author: engkhalideltaweel@gmail.com http://dx.doi.org/10.28991/cej-2021-03091634 © 2021 by the authors. Licensee C.E.J, Tehran, Iran. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).