We promise the concrete may crack! That is a natural for concrete, our job is to minimize them and try to control where they go. Concrete needs to have enough cement in it and a proper mix to hold up to the elements, and pressures on it from settling, ground vibration etc. We pour 4-5” thick, 32mpa. Concrete, aiming for 4.5” average, with 10mm rebar at approximate 24” spacing both ways. We also try not to stretch the expansion joints too far apart, they should be in close to square sections, not more than 10-12’ apart both ways. We guarantee the concrete will not come apart, or settle so there is a trip hazard, for 24 months from completion, or we will repair or replace at my discretion. We cannot control what happens to the surface so we don’t guarantee that so your best bet, if that is a concern, is to seal the concrete with a good quality concrete sealer every 2-3 years depending on wear, and use. We will gladly come and seal, or reseal the concrete for you at a reasonable cost.