The Paving Blog

Addressing a question I received via email today, so here goes -

Pavement cracks come from a small variety of sources.  Typically, both in asphalt paving and concrete paving, the sub grade below the roadway itself determines pretty much everything dealing with the heaving and contraction issues which severe weather induces.  Asphalt is nowhere as rigid as cement, but it can also crack under stress.  Naturally, no crack ever improves, after that point.  It is a matter of widening and becoming yer more glaring and severe, separated more so by continuing the same stresses and now even factoring in the presence of pockets of trapped water which will further erode the integrity by freezing itself and causing flaking or absolute separation.

Concrete, as a rigid monolithic piece, will always crack.  Even the best professionals understand this.  What typical highway construction specifications insist on is the presence of re bar, or rods of connecting metal, imbedded inside the cement itself, which will take the cracking and do not allow it to separate in any gross manner. Naturally, severe cracking will need repairing, but re bar gives the surface a chance to last longer as a viable road or driveway surface.

Typically, expansion joints are placed in concrete literally “inviting” it to crack along predetermined lines.  Once this is done, if it happens, then the preset position has been accounted for and dealt with.  Further damage would necessitate replacement of the concrete however, if the cracks appear elsewhere.

It is not a comfortable or productive feeling seeing a crack form in concrete.  As I stated above, cracks don’t “get better”. But they can be filled, reducing if caught on time, further damage.  Once weather and water are allowed inside the cracks, a surface is not long for this productive world.  Improper placement of the expansion joints is a very common reason for cracking.

These little patio pavers are perfect for a small budget and a do-it-yourselfer with some know how about sub surfaces. The advertisement says these can be “pressed into a lawn”, as if that were easy to do. While they may have enough surface area to “float” on a purely soil surface, if you are interested in a more long-term solution, my recommendation would be to use at least a bed of sand underneath, if not compact able gravel base material. Their primary use is for patios which typically doi not bear a great deal of focused weight, so their is less need for the stringent prequalifications involving subgrade strength and durability of, say, a driveway.

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Just the same, I would highly recommend just a bit of forethought and some base materials be applied to prevent a sinking of the corners and sides of each individual paving stone shown here. A result of a bad placement would be very unsatisfying and require reworking one more time - or repetitively during the years to come.The mud alone would make you no go back. Think permanent with this stuff. It pays of in the long run. A few hours more work once will save about 24 later.

So, ever wondered how they make those neat bricks used in paving?

A paving block making machine is a fascinating and very complex machine.  The best ones produce the pavers used in streets and on walkways, patios and driveways throughout the world, now, a modern paving alternative which is rapidly becoming a trade in itself. Inasmuch as paving blocks are now produced with PSI (Pounds Per Square Inch) ratings of up to 8,500 PSI, there is some magic in all this.

A standard city sidewalk minimum specification is about 3,500 PSI.  Curbs and gutters in standard city specifications are around 4,500 PSI.  Obviously, then, you can see that interlocking brick pavers rated at 8,500 PSI are a durable, very hard and, therefore, intriguing possibility. The fact is, many cities are now opting to pave city streets in these brick pavers. Their durable and modular basis means they will accept more abuse, for one thing, and the fact that they are applied as segments within a whole make them more flexible. thus lessening the impact of weather in terms of heaving and breaking.

The paving block making machine has the tendency to shake out all air pockets within the brick itself, one of the primary reasons for such a major step up in durability.  Using a finer sand and more cement, the products is also compressed at a high level inside the form of the machine itself.  As well, the best paving block making machine has an option for various patterns of construction, meaning a wide number of optional forms and products can be produced.  These machines are not for the light-hearted.  The deliver a fantastic product and are extremely pricey.

Circle paving has come full circle since the recent popularity has blown up the market for pre-cut stones and bricks. What once was an onerous chore of slicing and dicing bricks and stones by contractors, has now become a matter of ordering from producers of already-cut and already-formed pre-cut circles to match or to fit within an existing product.

Circle paving’s primary asset is purely aesthetic, although there is also a very distinct value-added aspect to modular paving in general. When you consider how almost all paving materials have historically been just huge slabs of cement or asphalt in modern times, the advent of landcaping’s increased popularity has led the movement towards and more aesthetically-pleasing exterior home environment in general. Another primary consideration has dealt with how a more interesting paving product measurably enhances the value of a home.

Circle paving adds a relatively easily installed alternative to monolithism. Instead of boring stretches of flat-colored and redundant lengths of driveways and patios, we now have the alternative of inserting these focal points of high interest, involving to the eye in their complexity and symmetry. So, along with the surprising and numerous choices now abounding with colors, we also now have an amazingly satisfying abundance of patterns and materials to please the eye and the sense. What was once an afterthought may now be included in the most intimate planning successfully and gorgeously.

We talked about paving kits in the last post, so today I’d like to focus on one specific type.

A circle paving kit is a relatively common modular construction made of differing materials but with a similar design trait: all the blocks or pavers inside the circle conform to produce a complete circle. In a design sense, it is a marvelous and frankly easier way of producing circular lines and an interesting pattern alternative. Curved lines always seem so striking inside the hard edges and durable properties of a paving material. One naturally suspects all paving to be some monolithic slab of asphalt or concrete and, yet, these delightful patterns can provide such a refreshing change from the boredom of standard monolithic paving. With the astounding new technologies of value-enhancing products now available as paving materials, the use of eye-catching patterns has become a New Wave in paving in general.

The wide range of materials testifies to the demand and interest in this sort of artistic license in what was once the very boring field of paving. From standard interlocking brick pavers to Terracotta-like stone angular placements within a system, circular paving kits offer a rapidly-installed and aesthetically-satisfying paving design alternative. Softer lines and more visual interest make circular paving kits a very substantially beautiful paving addition. The kits themselves are a step up in productivity. Once, an installer had to cut and fit himself, all the various parts of circular paving materials. Now, one can readily order them to match the pavers used surrounding these gorgeous circles.

Having discussed interlocking pavers as one option, as well as the size of the driveway, let’s talk about the low-cost option for driveway paving.

Faced with rising prices on just about everything any more, we often face a need to cut back costs on some of the items, that we once had bigger plans for. Things such as patios or the more exotic stuff like elaborate entryways, walkways and sidewalks bear on this, but driveways are the most cumbersome of all, in this case, owing strictly to the area involved. When we face a situation like this, a level head and some creative trimming can arrive at a place that we can still work with. Knowing the costs of any project prior to its installation is the key here. Extrapolating from a known figure allows us to come to some conclusions. I will now list 2 options:

Gravel and Base Material

Gravel does not have to look bad, nor does it need to be gravel, as such. The fact is the same base material we work with providing the sub grade for all paving projects can be utilized quite efficiently as a driveway surface. The virtues of base material are a few fold:

1: It compacts extremely durably and can be re compacted and reshaped at any point. Car tires do not really impact it as much as one would think, as long as a sufficient depth and compaction is reached. It is, after all, the structure upon which we base every single other covering.

2. It is in place when we want to upgrade. The next phase will be adding an overlay of cement or asphalt to an already-groomed, compacted area. The labor saving will be substantial in spades.

3. It is not unattractive. Well-compacted base material is the same material taken almost always from rock native to the area. It is almost always produced locally. Graded correctly, this material can allow water to run off appropriately and wash up revealing some fairly effective rustic color. In terms of “finishing elements”, it is also possible that another layer of different, more picturesque gravel could be added for color and general appearance.

The downside, of course, is in the fact that it is granular, therefore erosive. The granular nature will mean some rocks pop up out of the surface of a strictly ‘base’ driveway and, of course, this tends to increase and not decrease. So there is the maintenance aspect to consider. Attention paid to this will not be onerous at all, however, and takes a small amount of time to rectify and re compact.

As a landscaper, I have often encountered homes whose driveways were some testament to the cement industry’s able sales abilities. I have seen homes whose driveways were as large and expansive as the footprint of the home itself. The current move towards multi-car garages propelled an outbreak of enormous driveways, making me confess to an urge to do my best to ask for some better-reasoned approaches to the issue of driveway size.

While a nice big driveway can mean you have the enormity and ease with which to back up out of your garage and turn around inside your very own roadway, it also can seriously detract from the look and the intimacy a well-designed tract can offer.  Obsequious and over-large, driveways end up a glaring white surface which overwhelms rather that connects.  A certain sterile sensibility injects itself when I look at one of these edifices, and it makes it very hard indeed to mitigate when one tries to draw attention to a nice landscape. In terms of curb appeal, something this huge and essentially hostile could only appeal to a road builder or another concrete fancier. In short, I see a small design disaster. Here are some recommendations:

1:   Consider cutting the space down, somewhere.  Even if a curve can be made that intrudes a bit into the large surface, a mounded area can be formed there with, perhaps a small, weeping ornamental tree whose roots will never affect the driveway.  This would not only add a softer element automatically (the curving line) but it would post a perpendicular “relief line” to the entire picture. One could also plant items which could grow over onto the cement itself which would lessen the effect of the hard lines implicit in big driveway edges.

2.  Consider as well your need for so much space.  What is it used for?  If it is merely used to back up and turn around inside, then consider backing straight out as an option.  As far as absolute necessities are concerned, the contrast between the comfort level of having an enormous space in which to reverse your car, compared to the inevitability of maintenance issues and that of the resale value and curb appeal is pretty striking.

Frankly, in the end, the value of appealing and objectively pretty lines in the design of a driveway is as important as the surface.  Clean and congruent designs of driveways indicate a level of care and of involvement.  They are more welcoming and possess an incredibly more powerful sense of curb appeal and of general warmth.