AASHTO PP 63:09(2014) Standard Practice for Pipe Joint Selection for Highway Culvert and Storm Drains.
5.1.1. For nonperforated pipe, a determination must he made as to the acceptability of allowing infiltration and/or exfihration through the pipe joint. If infiltration of backfill material is not a concern and water movement through the joint is not a concern, then the default or soiltight joint should be selected for this type of application. The purpose of the soiltight joint is to maintain backfill integrity and pipe alignment and to join the ends/sections of pipe together to allow a continuous flow of water while maintaining the interior required gap between sections. This joint will limit the intiltration of soil particles in the backfill material to particles that will pass through a No. 2(X) sieve.
5.1.2. For nonperforated pipe where infiltration of backfill material is a concern, the designer should examine the composition of the backtIll material. If there is a high percentage of soil tines (Note 1) finer than the No. 2(X) sieve, then a silt-tight joint should he selected for most applications.
Note 1—A high percentage of fines are defined as more than 35 percent passing the No. 200 sieve.
5.1 .3. If water movement through a joint is a concern, a leak-resistant joint or a special design joint should be selected.
5.1.4. If limited joint leakage is acceptable, a leak-resistant joint shall be specified. This joint will limit water leakage to a maximum rate of 200 gallons/inch-diameter/mile/day for the pipeline system for a specified head or pressure.
5.1 .5. If limited joint leakage is not acceptable, a special design joint shall be specilied.
5.2. Sections 8 and 9 should be consulted once the type of joint has been selected. These sections present various methods for constructing a soiltight, silt-tight, leak-resistant, or special design joint for each type of pipe material.
5.3. To ensure proper joint performance. the pipe joint integrity shall be established by the pipe joInt manufacturer prior to shipping the pipe, and further vcritIcd in the field by the contractor as witnessed by the project Inspector. The manufacturer shall perform plant verification tests when specified in accordance with the Plant Test Requirements for the appropriate pipe material in Section 6. This will ensure a suitable pipe joint is being delivered to the job site. Upon completion of the installation of the pipe, field verification of any leakage requirements by visual inspection or applicable testing shall be performed by the contractor and/or engineer when specified in accordance with the Field Test Requirements outlined for the appropriate pipe material in Section 7. Failure to pass either one of these requirements when specified is cause for rejection of the pipe.
6.1.1. Soiltight joints are specified as a function of opening size (maximum dimension normal to the direction that soil may infiltrate), channel length (length of the path along which the soil may infiltrate), and backfill particle size. If the size of the opening exceeds 1/8 in., the length of the channel must he at least four times the size of the opening. No opening may exceed I in.AASHTO PP 63 pdf download.