Bleach is a very commonly used multi-purpose cleaner, commonly found in the home that actually will help to keep your concrete looking good. Unfortunately, it’s very unlikely that bleach will make any difference to efflorescence or oily and greasy stains.
Instead, you should use bleach if you have an issue with mold or mildew. These are common in cement basements, but it can happen outdoors as well, one of the big benefits of bleach is that you can use it on both sealed and unsealed concrete.
If you do use bleach, you should never use full-strength bleach because at it’s full strength, it can be quite powerful and could cause damage to a variety of surfaces. For most uses, you can take ¾ cup of bleach in a gallon of water. Apply the diluted bleach solution with a mop, let it sit for around 5-10  minutes, then rinse it away with a pressure washer.
Do not let your pets anywhere near the area where you are using bleach and if you are using it indoors, making sure to ventilate the room. I actually recommend using a respirator to ensure that you don’t inhale the bleach fumes. Bleach can hurt or kill your plants, so don’t let it run over them or get into the soil. Spray your plants with clean water and then cover them with a tarp before spraying or spreading bleach nearby.