introduction Joint Sealants (continued) concrete pipe Cement Cement sealants consist of cement paste made with water. The joint surfaces should be clean and soaked with water immediately before the joint is made. A layer of cement paste or mortar is placed in the lower portion of the bell or groove of the installed pipe and on the upper portion of the tongue or spigot of the pipe section to be installed. The tongue or spigot is then inserted into the bell or groove of the installed pipe until the sealant material is squeezed out on the interior or exterior surfaces. The annular joint space should be completely filled and the abutting joint sections flush and even. Rubber Whereas concrete pipe has a number of rubber gasket options available, precast concrete box sections do not allow for an attached gasket. As such, roll-on gaskets are utilized by placing a rubber strip with adhesive around the tongue or spigot into position as the joint is assembled. stormwater treatment technologies Pictured above - Kent Seal butyl (rubber) gasket coil. External Bands Cement mortar bands are placed around the exterior of the pipe joint. A slight depression is excavated in the bedding material to enable the mortar to be placed underneath the pipe and the external joint surface cleaned and soaked with water. Canvas or cloth wrapping is used to hold the mortar as it is placed. Backfill material should be placed around the pipe immediately after the mortar band is in place. Mastic Mastic sealants consist of bitumen and inert mineral fillers. The sealant is applied to the tongue or spigot and inserted into the bell or groove. A sufficient amount of sealant should be used to fill the annular joint space with some squeeze out. box sections Notes: Manufacture of box sections includes supply of concrete product only. Butyl rubber coils are available upon request, but do not constitute a water tight seal. Sealing is not the responsibility of Lafarge, including recommendation of sealing product, sealing contractor, or sealing procedure. It is recommended, however, that the groundwater conditions at the subject site be taken into consideration, as hydraulic gradients may impact sealant performance. manhole and catch basin material LAFARGE PIPE eMANUAL PAGE 13