Ahmed Arafat

The current study deals with the field geology, petrography, and geochemistry of some Egyptian granitic rocks and its suitability for construction materials. Also, the present work aims to determine the physical and mechanical properties of some granite in the northeastern Desert of Egypt to detect their suitability for ornamental stones. Granitic rocks are regarded as one of the most significant commercial commodities and are utilized for a variety of uses, including as decorative stones. The main applied tests of physical and mechanical properties include compressive strength, apparent porosity, specific gravity, water absorption, abrasion resistance, thermal expansion, weather and frost resistance, and acidic resistance. The study district geologically is forming moderately high mountainous ridges with hard topography and curly peaks. The collected sample petrographically divided into biotite monzogranites, alkali feldspar granites, and riebeckite- arfvedsonite granites (peralkaline granites). Meanwhile, the chemical classification of these granites was distributed between the granite, granodiorite, syenodiorite, monzogranite, syenite, and alkali granite fields and all the studied samples have alkaline to peralkaline affinity and metaluminous to peraluminous nature and also classified as I-type orogenic granites and A-type anorogenic granites. The studied samples were cutting according to the American Society for Testing and Materials specifications (cubic shape) for detection the physical and mechanical properties. The compressive strength ranges from 795 to 979 kg/cm3, apparent porosity ranges from 0.35% to 0.58%, specific gravity ranges from 2.67 to 2.79 gm/cm2, water absorption ranges from 0.13% to 0.22%, abrasion resistance is good, thermal expansion ranges from 0.02 to 0.06, weather and frost resistance are good, and acidic resistance are good. It should be noted that the studied granitic samples showed good results according to mechanical and physical tests. So that it can be used in decoration purposes and construction materials

The present paper focuses on the geology, petrography, and geochemistry of the well-known Dokhan volcanics encountered in the northern part of the Eastern Desert of Egypt. The basalts, andesites, rhyolites, and agglomerates exposed at the Makhar Seal (flood plain) as well as Wadi Abu Zoghot, Wadi El-Ghafiryia, Wadi Al-Radah Luman, Wadi Al-Ushsh, Wadi Umm Sidrah, and Gabal Ghuwayrib are herein examined as sources of coarse aggregate in concrete mixes. A representative total of 28 samples—collected from different Dokhan volcanics—was studied in terms of field geology, petrography, and geochemistry wherein a variety of experiments related to construction material validation apply. The petrographic examination revealed that the studied Dokhan volcanics consist of basic, intermediate, and acidic volcanic igneous rocks. These rocks are represented through basalts, andesites, imperial porphyry, dacites, rhyodacites, rhyolites, and their pyroclastics. Furthermore, the applied geochemical analysis indicated that the studied Dokhan volcanics are alkaline to sub-alkaline, calc-alkaline and classified as basalts, basaltic andesites, andesites, trachyandesites, trachydacites, trachytes, and rhyolites, indicating an initial potential as aggregate for concrete mixes. Finally, the results obtained from incorporating Dokhan volcanics as aggregates in concrete mixes demonstrated a significant improvement in regard to the properties of the comprising concrete mixes. Herein, a higher compressive strength was witnessed after 28 days for Dokhan volcanic concrete, when compared to concrete comprising dolomite aggregate, amounting to an average increase that exceeded 36%.