Replacing damaged pavers
Although cracked or chipped pavers are rare occurrences, accidental breakage does occasionally occur. One of the benefits of ICPs is the ability to remove individual units and replace them with new ones. (At the completion of the initial project, ideally the contractor should leave extra pavers at the site for this purpose, thereby avoiding any noticeable variation in colour because slight variations can occur from traffic-borne dirt accumulating on surrounding pavers.)
Removal can be accomplished by carefully wedging individual pavers out of position using hand tools such as a metal pry bar or screwdriver, although specials tools are also now available. Removal can be made easier by digging out as much joint sand as possible with a putty knife and/or by shop vacuuming and wetting the joint sand.
The next step is to begin prying on the short end of the paver. It will rise a small distance with each pry. Once high enough, it can be grabbed and pulled free. After the first paver is removed, additional units will easily follow, if required. In some cases, pavers may need to be broken with a cold chisel and maul to enable removal. Protective eyewear should always be worn during this process.
It is all about the sand
The sand which fills the joints between interlocking segmental unit pavers plays an essential role in the long-term performance and appearance of the system. The joint sand and the edge restraints installed around the perimeter of the surface help to create and maintain ‘interlock’ between the neighbouring units. The term interlock describes the transferring of vertical loads (applied to the surface of the pavement), to a horizontal direction exerted on the sides of the pavers. The tightly compacted joint sand (and edge restraints) prevents the individual units from losing interlock and moving in isolation to each other. When joints are tight and the sand in them is secure, the result is an incredibly strong, yet flexible pavement system that can be used in a wide range of applications.
Most pavers are designed with spacer ‘nibs’ that help maintain a uniform 2- to 4-mm (0.7- to 0.15-in.) space between units. This space allows fine sand grains, which are applied after placement of the pavers, to completely fill this space. (During construction, pavers are placed and compacted with a vibrating plate compactor except around pools where a 254-mm2 (10-in.2) hand tamper or rubber mallet is used.
After the first compaction, fine, dry sand is swept into the joints. The best sand by far for this application is called mason sand, which is used to make mortar. Limestone screenings should never be used.)
This sand, however, without treatment of one form or another, has a tendency to erode over time as the result of traffic, wind, manual or power sweeping or cleaning, insects (such as ants), and the combined effects of rain, snow, and ice. When the sand is lost from the joint space it is typically replaced by soil or dirt. When this occurs, it creates conditions that will often result in the growth of weeds.
Stabilizing joint sand
Over the past two years, a number of companies have developed products that stabilize and protect ICP pavement systems from sand loss. These products stabilize joint sand and can also accelerate the natural weathering processes. They effectively and permanently bind the sand particles together in a flexible, yet durable state. Joint stabilizers have proven important to the hardscape industry as they prevent weed growth, which has long been a complaint about ICP systems.
In addition to avoiding sand loss from the erosive forces of wind, water, and other elements, which can lead to the settlement of pavers, an additional benefit of the installation of a joint stabilizer is the increased service life and durability it provides to the entire pavement installation. The growth of weeds is the beginning of the deterioration of the entire pavement installation, and once the process has begun it is difficult to control and expensive to repair. It makes much more sense to install a joint stabilizer at the time of installation or after a proper cleaning.
Brian Burton operates a multidisciplinary firm that specializes in website design and development, and technical business writing. The firm also assists companies interested in selling goods and services to governments and institutions. He can be reached via e-mail at burton@award-bid-management.com.
