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.

A block paving kit is a packaged product complete with all the paving necessities to complete a specific task.  People often speak of “kits” as if they were utterly uniform in size and scope, but obviously paving needs are a different animal altogether.  There are very, very few applications in paving blocks which resemble one another and there is some satisfaction to be taken from this. Nevertheless, calling a packaged amount of pavers a “Kit” is apt.

The “kit” referred to here presents a preset, pre-patterned modular system of paving materials ready to install in a predictable and preset pattern. Beginning at an edge, one merely follows the directions given relating to the pattern and periodicity of angles and any odd insertions, such as circles or artwork.  An entire driveway, no matter the size, therefore becomes a “kit”, recognizeable owing to its redundancy. The puzzling aspects of the modularity soon take on the normality of any other craft or project inasmuch as they become predictable, requiring little tho0ught other than following directions for installation.

Kits make life a lot easier.  Fortunately, nor does “paving block kit” have to take on some less-than-acceptable connotation.  It is what it is, a kit for assembling a complex and satisfying bit of paving or patio surfaces, complete with instructions!

After the last post, another low-cost option for driveways came to my mind. Low-cost enough to carry on the discussion with -

Asphalt is the least expensive of all the different surfaces offered applied above the base itself. It has all the benefits and detriments of monolithic surfaces, in that it is intact and total as a surface. It is one color and consistent in that. It can be applied in shapes without form material, leaving curved edges, indentations at a designer’s whim, and without the forming and handwork of cement.

Asphalt’s only real disadvantages are that is has a definite life span and that it is monolithic, a problem when dealing with heaving and contracting sub soils in severe cold. Blazing heat can also act to loosen the integrity until it flakes, chips or loses durability in general as well.
There are protecting sealers, such as Slurry Seal that can be applied over the top and which can act to extend the life of an asphalt driveway, but these are required pretty much every year in more severe climates.