Glass is one of the oldest and most versatile materials known to man through ages. Glass occurs naturally as a volcanic ash 🌋 known as obsidian. Artificial glass was first made about 4000 years ago. The term glass is normally used to describe a particular state of matter, known as glassy or vitreous State, which is obtainable when a liquid cools without crystallization taking place, With solid properties characterized by its brittleness, hardness, transparency and chemical inertness.
Surface water ( i.e., rain water) that falls on the ground surface such as; open field, paved areas or road surface, roof tops etc are channeled to a main drain naturally or through a constructed channel which is referred to as drainage. Procedure for construction of a common drainage (trench) (1m x 1m U drainage) (reinforced). includes; I. Marking Of Alignment: The surveyor marked out the alignment for the trench to be dug. II. Digging/Excavation: The surveyor marked out the dept of the trench to be excavated with a mechanical excavating machine. For a 1m x 1m drainage, the mathematical process of obtaining the required dept is to sum together the dept of the required drain + base + blinding. For dept: A drain of dept1000 mm, base of 150 mm and blinding of 50 mm. Hence 1000mm + 150mm + 50mm = 1200mm (1.2 m) So an excavation of 1200mm (1.2m) is required...
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