Joined: July 2004
||Posted: 04 Sep. 2018,09:51
Q1 - Herringbone is the strongest layout using rectangular blocks. It's also used with shaped or dentate blocks as it eliminates long, continuous joints that could slip or creep.
Q2 - it can be quantified using a complex calculation involving Finite Element Analysis, but that is PHD level stuff, well beyond the remit of this site. Over 10 years ago, I sat through a terminally boring lecture which attempted to explain how it is done and that is 2 hours of my life I will regret wasting to my dying day!
Q3 - hexagonal blocks are a shaped block (obv!) and so the horizontal interlock is good, but the size of the elements then determines just how good. The bigger the hexagoons, up to a limit of around 400mm, the better the interlock. However, keeping hexagonal blocks truly aligned is no easy task and any drift in the patternm is a potential weakness.
As LLL pointed out, a far bigger factor on pavement stability is adequate edge course restraint. Due to climatic variations, the systems used in your country are not used in Britain and Ireland. We can get away with using concrete whereas that would be crippled by a single winter in the north of North America, hence the use over there of various restraint systems of highly variable effectiveness. I'd focus more on what would work best for your project, and also look at using intermediate restraining courses on such a slope, rather than get bogged down on which laying pattern would give a few percentage points greater horizontal interlock.
Site Agent - Pavingexpert