While we deal with the structure and durability of the paving materials themselves, there is another completely separate consideration which bears attention: the spaces between the pavers. Improper filling and inappropriate colored grouts and even the sands between manufactured paving stones can add or detract immeasurably to the final result, strictly aesthetically speaking. Where the spaces are small, it still bears on the issue. Pavers reveal as little as an eighth of an inch between them, but they are so numerous and so evident, the appropriately colored sand used for dry grouting can be amazingly helpful. Needless to say, where the spaces between the stones is wider, we see yet another combination of opportunity: either helpful or harmful to the overall effect.
I have included some pictures of what the better-looking grouts can accomplish. In a sort of whimsical view, we also have the very cool area of fantasy and serendipitous grouting that actually can make stones look literally fun. What you see in these examples are examples of successful grouting – where the use of the proper grout can make the colors stand out more or can even overtake the overall look with some entirely different effect.
The general rule of thumb is to provide some congruent tone and texture that takes a back seat, highlighting the stones themselves. But there are also case and situation where it can be equally desireable to highlight the grout in order to present a different effect.
Bear in mind, there are sealers we can add to the poaving itself to lock these grouts into place. Apparently piled up sand can be sturdier than one initally believes owing to a sand-lock sealer which binds it in a sturdy fashion.