Political boundaries are often formed by physical boundaries. An example of this is the Rio Grande River that separates the US from Mexico. An ethnographic boundary or a cultural boundary is a boundary line that runs along differences in ethnicity.
Steel has a density of about 490 pounds per cubic foot, which is more than three times the density of concrete, so the generally accepted density of normally reinforced concrete is 150 pounds per cubic foot which results in a cubic yard weighing 4050 pounds, but this depends on the quantity and grade of the rebar used.
Weight of 1m3 of concrete? A cubic meter of concrete weighs around 2.5 tons. The weight will  vary somewhat with the composition, but usual concrete mixes (per  cubic meter) contain 350 Kg of cement, â¦ 700 Kg of sand, 1,200 Kg of  chippings and 150 liters of water.Jason Harmon.he unit weight of the Reinforced concrete is 25 Kn/cu.m i.e., if u cast a concrete cube of dimensions 1m width, 1m breadth and 1m depth, this cube weighs 2500 kg.