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 mix of portland cement, an aggregate, water and other additives that give the mix certain characteristics. Aggregates vary depending on scale, colour, strength: All measurements are given as volumes, or relationships of volume. The dry materials are mixed first. Water is added to the dry mix. Do not add too much water; the drier the mix, the stronger the final product. (Excess water stays trapped in the cured cement.) How wet to make the mix is a function of the process: casting in a mold will need a wetter mix that slumps into place. Applying the mix to a wire mesh will need a drier mix that feels more like clay and stays in place until it sets.