Forum: Block Paving
Topic: Paver pattern vs shape in residential driveways
started by: LeroyMakins2018
Posted by LeroyMakins2018 on 03 Sep. 2018,12:25I've got ~600 linear feet of a residential driveway I am looking to pave with clay brick pavers. The drive has a 300' section from the main road, as well as a 300' teardrop-shaped section.
The site has approximately 6 feet of fall over the 300' from the road to the bend at the teardrop (this point being the lowest point in the site).
For various reasons (slope, inexperience, "possibly" knowing how my other projects have turned out . . . ), I'm thinking it would be a good idea to lay the drive in the "best" way possible, with the expectations that this might accommodate any imperfections in "craftsmanship".
I've read here and elsewhere that a herringbone pattern (< elsewhere >) is a better choice for a driveway due to its bonding strength.
My primary question is - is there a way to *easily* calculate the strength of the pattern to hold together under optimal conditions, or are there too many variables?
If not, then in general:
Question 1: is this correct (herringbone - best pattern strength)
Q2: How much "better" is a herringbone over its next-closest pattern - if that can be quantified
Q3: One option I have access to is a < Hexagon-Shaped Clay Brick Paver >, which seems each brick would have equal force distribution amongst its neighbors. How would this shape compare?
Thanks - this site and forum have been wonderful!
Posted by lutonlagerlout on 03 Sep. 2018,12:41no engineer here ,but the big answer is that yes 8 by 4 inch blacks laid herringbone gives the best interlock and strength on driveways, we dont get too many hexagon blocks on driveways here
if I recall correctly there used to be a "W" shaped block that was often used on petrol station forecourts and that was a strong bond because of the level of interlock
on such a long drive you need decent kerbs or edge restraints
Posted by Tony McC on 04 Sep. 2018,09:51Q1 - 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.