@VenusWorldofThamarai
tnpsc, group 4, std 6, science, tamil, cement, mortar, concrete, RCC, portland cement ,lime stone, sand, water, gypsum, epsum, water, gravel, plaster of paris, physical change, chemical change, salt, Joseph Aspidin, magnesium sulphate hydrate, calcium sulphate hydrate, silica, calcium carbonate, sodium carbonate, sodium hydtroxide, oil, soap, plastic, fibres, jute, cotton, coir, polyester, nylon, rayon, bio plastic
