To answer this question which is heavier cement or sand, let us understand specific gravity, the specific gravity of material gives us how much more or less dense the material is than water.
Water has a specific gravity of 1.000 (near 4°C). If a material is more dense than water, then its specific gravity is greater than 1. If it is less dense than water, then the specific gravity is less than 1.
The specific gravity of sand is 2.6 – 2.7 and that of cement is 3.14 – 3.15, i.e. for the same volume occupied by cement and sand, cement is “3.15/2.8 = 1.16 times”heavier than sand.
Hope above is clear.