Concrete strength is a function of several factors Strength of Cement - portland cement is typically used. Fire limestone to get lime, add fly ash and other a

Concrete strength is a function of several factors Strength of Cement - portland cement is typically used. Fire limestone to get lime, add fly ash and other additives for increased strength. Ratio of Water to Cement is important to get a complete reaction, but dont add too much water. Aggregate - angular aggregates provide the cement something to stick to and distribute the stresses evenly. You want a well graded aggregate, including sand particles up to larger chunks of rock. In my part of the world the aggregate is typically crushed limestone. Add clean sand for different mixes. There are other chemical additives that will increase strength, workability, and the speed of cure. Since reaction of water to cement is exothermic - on the really high tech monolithic pours they're using technology to carry away the waste heat. You want the whole mass to be at the same temperature to reduce the internal stresses. There are actually spherical glass orbs you can add to your concrete if you want it light-weight. Floating concrete is a thing. This comes at the expense of strength.