Interlocking pavers made from concrete i.e. a combination of crushed natural stones, sharp sand and cement are the most common in use across Nigeria. They come in various shapes and sizes, although in specific colors (especially brick-red, brown and natural); fitting or locking perfectly into each other when installed to give a firm longitudinal bearing and surface brilliance throughout the entire area of application. These interlocking stones are often used in external flooring in buildings, walkways and on roads.
However they continue to suffer from issues ranging from poor strength to low staying power especially due to poor production and faulty installation as well as their inability to sufficiently withstand weathering, tension forces and frequent trampling which they were originally designed to accommodate. This is not abnormal because pure concrete only perform well against compression and will fail under tension if not sufficiently reinforced. In other to make up for these shortcomings, there have been increasing calls for the introduction of reinforcement in concrete paving stones; a call which seem to fall into deaf ears.
Now with the invention of a new variant of pavers made from either pure or recycled rubber a few years ago, the option scale has widened. This 50mm thick rubber dog bone interlocking pavers (also referred to as I-Pavers or Bow-tie pavers) is increasingly gaining popularity amongst builders, home owners and developers across the globe owing to its toughness, low-impact surface condition, non-slip property and durability (up to 50 years) even though it is not good against fire.
Despite all these admirable qualities, it is still cheaper than the concrete or brick type, a lot easier to produce, install and maintain and comes in a wider range of exciting colours, designs and patterns. Its low-impact surface quality make it the delight of children when used in their play grounds because even when they fall to the ground while playing, they won’t sustain as much injuries as with the concrete or brick type pavers.
Together with its effective noise control potentials, it is very suitable for use on camp grounds, sport grounds, studios, schools, relaxation centres, resorts, restaurants, supermarkets, bus stops, hallways, walk-ways, road pavements, car parks, estate roads and residential homes. Although there is no known manufacturer of this product in Nigeria, this line of business is highly profitable elsewhere hence should be encouraged back here to reduce importation and create more jobs.
The production processes are beyond the scope of this article but the preferred mode of installation is meticulously described thus;
Prior to installation, a shallow or topsoil excavation should be performed on the ground/earth upon which the pavers will be laid up to 150mm depth after adequate site preparation.
Note: Where the sub-soil shows high quantity of clay, shallow excavation up to a reasonable depth (say 200mm beyond the top-soil excavation) should be carried out to remove the clay-saturated soil and replace it with highly draining soil like mined sharp sand. This is the best practice for installing all types of interlocking paver including the traditional (concrete) interlocking stones. The reason is that due to the plastic nature of clay, it tends to retain water/moisture which should have drained quickly and naturally into the earth; expanding and contracting abnormally with change in weather conditions at different times of the year, forcing uneven settlement and surface cracks which impedes on the stability of the pavers and displaces them in various directions.
- On grounds with high water table (i.e. swampy or water-logged areas), a damp proof material should be laid flat in between the sand bed and above the water table/level. In such cases the interlocking pavers should be sloped slightly during construction such that it empties all surface water into a nearby drainage, since the damp-proof barrier will prevent water from soaking away beneath the surface.
- Above the natural ground level, smooth or sharp sand should be used to fill the earth and make up levels and to receive the pavers directly. Do not use earth filling (or re
d sand) here. This surface fill should be properly treated with eco-friendly herbicides. No cement is required to install rubber dog bone pavers.
Once the sand filling is completed, it should be well compacted till it is relatively stiff and firm. Using a preferred style (e.g. slanting/angular, perfectly vertical or perfectly horizontal patterns), the tiller pushes and locks the pavers into the soil and into each other respectively in an organized manner up to half the depth of the pavers with the use of a soft mallet (for manual installation). A stopper (e.g. a thin fibre frame) should be installed at the open ends of the paved area to prevent the systematic collapse of the entire set-up by weathering.
- In the end you have an exquisitely finished paving that can stand the test of time.