Resistance to infiltration of groundwater and backfill material

Resistance to exfiltration of sewage or storm water

Ability to accommodate lateral or longitudinal movement

Strength to handle shear or vertical movement

Pipeline continuity and smooth flow line

Allow infiltration of groundwater for subsurface drainage

Ease of installation

In addition to the inherent strength of a pipe constructed using reinforcedconcrete, the pipe joint can be designed to meet different sealingrequirements, with the ability to accommodate lateral or longitudinalmovement by using several joint options including mortar, flexible jointsealants, rubber gaskets and external sealing bands.

Concrete joint designs provide the following performance characteristics:

As infiltration and exfiltration standards have changed considerably over thelast century, so has the performance of concrete pipe and concrete pipejoints. A long-time proven solution, concrete pipe offers the design engineerseveral different joint types, depending on the application, to meet theutmost demanding project specifications. Because of its superior durability,strength and joint system performance, concrete pipe remains the pipe ofchoice for engineers and owners of drainage and sanitary sewer projects.

Two common misconceptionsoften shared by competingproducts are that concrete pipeis inferior because of thenumber of joints, and it’s notwater-tight. However, these arefalse. With an increasednumber of joints, line and gradeare maintained and checkedmore frequently, pipe lengthscan fit and be positioned instandard trench boxes moreeasily, and longitudinal stressesin pipe walls are relieved whenpipelines encounter non-uniform bedding foundations.What’s more, RCP joints can bedesigned to be watertight,soiltight and silttight. In mostregions, soiltight is thestandard specification.

Concrete Pipe Joints: Your Best Choice

ADVANTAGES OF CONCRETE JOINTS

ACPA Key Issue Statement

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Rubber gasket joints (below, example A and B) – leak-resistant and

watertight joints

Preformed flexible joint sealants (below, example C) – soiltight and silt-

tight joints

Mortar tongue and groove (below, example D) – soiltight and silt-tight

joints

When comparing the performance of jointing systems between concretepipe and alternate products, one should review the standard specifications ofeach product and be aware of what is and is not included within thesuggested standards. Precast concrete pipe joints are manufactured in twobasic shapes: tongue and groove, and bell and spigot. The types of jointsinclude:

A pipeline’s function generally determines the performance requirements ofthe pipe joints, and today’s concrete pipe manufacturers offers several typesof joints that meet stringent industry and national performance standards.Whether the purpose is to convey sanitary sewage or storm water, joints aredesigned so that when sections are laid together, they will make acontinuous line of pipe with an interior free from irregularities. Joints can bedesigned to be soiltight or watertight with the ability to accommodate lateralor longitudinal movement, and strength to handle shear or verticalmovement.

Concrete surfaces with opposing shoulders on both ends, such as the belland spigot joint, generally utilize a rubber gasket for sealing. Preformedflexible joint sealants or mortar are used for lesser performance requirementsor where the product shape dictates the type of seal.

TYPES OF JOINTS

DESIGNED TO PERFORM

The concrete pipe industry offers several joint systems to satisfythe broad range of performance requirements. Consultation withlocal concrete pipe manufacturers will provide information on theavailability of the various joints.

Although alternate materialsmay use rubber gaskets, theuse of a rubber gasket doesnot by itself ensure thatdifferent joint types are equal.Designers can utilize ASTMStandards to specify fordesired performance, but inthe case of alternatematerials, additionalguidance may be required.Concrete pipe joints aregoverned in nationalstandards by better, moredetailed designs with tightertolerances and higher testpressures. Rubber- gasketedconcrete pipe joints meet thestringent requirements ofASTM C 443. Additionally, theproject owner benefits fromthe concrete pipe joint’sinherent strength and rigidpipe design to ensure line andgrade and maintain jointintegrity.

Typical cross-section of tongue andgroove joint with flexible mastic

sealant.

Typical cross-section of tongueand groove joint with mortar

packing.

Typical cross-section of opposingshoulder type bell and spigot joint

with a confined o-ring rubber gasket.

Typical cross-section of opposingshoulder type bell and spigot jointwith a single offset rubber gasket.

A B

C D

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ASTM and AASHTO standards apply to concrete products’ joints. Theversatility of joints allows the designer to match project requirementswith the appropriate joint and/or seal. Note that joints for most pipeproducts are specified in separate standards than the pipe and precastmanufacturing and design standards.

ASTM C 1103 Standard Practice for Joint Acceptance Testing of InstalledPrecast Concrete Pipe Sewer Lines provides procedures for acceptancetesting of joints by air or water tests of installed concrete pipe joints. ASTM C 969 Standard Practice for Infiltration and ExfiltrationAcceptance Testing of Installed Precast Concrete Pipe Sewer Linescovers procedures for testing installed concrete pipe sewer lines usingwater infiltration or exfiltration acceptance limits to demonstrate theintegrity of the joints. ASTM C 1214 Standard Test Methods for Concrete Pipe Sewer Lines byNegative Air Pressure (Vacuum) Test Method covers procedures fortesting 4- to 36-inch concrete pipe sewer lines using the vacuum testmethod.

There are three different field test methods to verify concrete pipe jointdesign, for vacuum, air or water:

1.

2.

3.

Strength: concrete isinherently strong Project-specific jointconfigurations Accommodates lateral orlongitudinal movement byusing several joint options

MortarFlexible joint sealantsRubber gasketsExternal sealing bands

Design Versatility: Concretepipe comes in the shape, sizeand joint configuration forvirtually any drainage program

STANDARDS

FIELD TESTS TO VERIFY JOINT DESIGN

ADVANTAGES OFCONCRETE JOINTS

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