Vietnam is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, Thailand across the Gulf of Thailand to the southwest, and the Philippines, Malaysia and Indonesia across the South China Sea to the east and southeast.[d] Its capital city has been Hanoi since the reunification of North and South Vietnam in 1976, with Ho ...
Cement. 1  Cement is a binder. Similar to flour in a recipe, the purpose of cement is to hold the other materials together. 2  Concrete is a composite of aggregate (such as sand or gravel), cement, and water. Itâs like a cookie. 3  The basic composition of mortar might seem similar to concrete, but what really sets it apart is how it is used.
Concrete is a type of artificial stone made by mixing dry aggregate (sand or gravel) and cement, then adding water. This makes a soft mix that can be molded easily or transported in a rotating concrete mixer. Different types of concrete can be made by varying the basic ingredients.oncrete owes its strength to the way in which water and cement combine chemically and bind together the particles of aggregate into a very dense mass. Allowing concrete to dry slowly means the concrete stays moist for longer so the chemical reaction is more effective.