True, I meant pre-mixed bag of cement + sand. >Even if you used just cement and water I think you would get more than 12L from 25kg. The thing will crack very

True, I meant pre-mixed bag of cement + sand. >Even if you used just cement and water I think you would get more than 12L from 25kg. The thing will crack very soon. The density of concrete is around 2.4g/cm3