Sand Set Paver Installation
This type of installation is the most common paver installation. It can be used in a variety of applications including residential driveways, patios and walkways, commercial plazas, even parking lots and roads.
It is important to remember that the amount of base rock underneath the pavers and how well it is compacted is directly related to the strength of the installation. Each site must be evaluated to determine the proper type and amount of base rock to be installed. However, there are general guidelines for the amount of base necessary for each type of installation. We recommend placing 6" - 8" of rock for residential patios and other pedestrian applications. For vehicular applications such as a driveway, a minimum of 10" compacted rock is required for sufficient installation strength. Where heavy traffic or where large vehicles such as semis or fire trucks will be travelling, 18" of rock or more is recommended. Proper base construction is crucial to a long-lasting and problem-free paver installation.
The amount and type of sand used for a paver installation is important in order to achieve interlock,which is what gives a paver surface its strength. The sand acts as a bedding layer, helping to level the pavers as they are installed and compacted. Sand should not be used to fill depressions in the base, as the depressions will be reflected in the paver surface within a few weeks or months. The sand is screeded to a an even depth and the pavers are placed on top. A 1" sand layer is ideal. It is not recommended to compact the sand before pavers are placed on top, as the degree of potential interlock is lessened.
It is recommended that a course sand such as concrete sand be used for the bedding layer, as opposed to mason's sand or fill sand. Mason's sand is too fine and may produce a wavy appearance on the surface of the pavement. Bedding sand should conform to the requirements of ASTM C 33, as shown on the table below:
After the pavers have been placed on the bedding sand, the pavers are compacted with a vibrating plate compactor. As the pavers are compacted, the bedding sand works its way up into the paver joints from underneath. This, along with the joint sand applied after the initial compaction, locks the pavers together and gives the pavement a type of load distribution known as interlock which is a unique aspect to concrete pavers.
Geotextile fabric may be used in areas where soil remains saturated part of the year, where there is freeze and thaw, or over clay and moist silty subgrade soils. As a separation layer, they prevent soil from being pressed into the aggregate base under loads, especially when saturated, thereby reducing the likelihood of rutting. When geotextiles are used they preserve the load bearing capacity of the base over a greater length of time than placement without them. Woven or non-woven fabric may be used under the base with a minimum equivalent opening size of No. 30-50 sieve.
Geotextile fabric is not necessary as a separation layer between the sand course and the base course, provided the aggregate used in the base has the proper amount of fines. If there is too little fine material, the bedding sand will migrate down into the base. However, if a base material with the proper gradation is used, the base will choke off any sand migration.
Please click on a file below to view a detailed cross section:
If you have any further questions or would like to dicuss a project, please follow the "Contact Us" link above or call our office at (503) 579-5560.
MODULAR PAVING SYSTEMS, INC.
The Northwest's Premier Interlocking Concrete Paver Specialists Since 1975.
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