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Concrete Repair Terminology (J-L)
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Concrete Repair Terminology is prepared by the International Concrete Repair Institute. The cross-referenced terms provide definitions for commonly used words in concrete repair, restoration and protection.

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Revised April 2019

A   |   B   |   C   |   D   |   E   |   F   |   G   |   H   |   I   |   J-L   |   M   |   N-O   |   P   |   Q-R   |   S   |   T   |   U-V   |   W   |   X-Y-Z

- J -


an integral covering which is applied over an existing structural element, e.g. a concrete pile, whose primary function is to strengthen or provide environmental protection, or both.


hand-held mechanical breaker for removal of concrete.

jaw crusher

boom-mounted mechanical crusher for removal of concrete from decks, walls, columns, and other concrete members where the shearing plane depth is 6 ft (1.8 m) or less; pulverizing jaw attachment can debond concrete from steel reinforcement for recycling purposes. (See also mechanical shearing.)


a physical separation in concrete, including cracks if intentionally made to occur at specified locations.

joint, articulated

a joint with movement limited by restraint.

joint, cold

an unplanned joint or discontinuity resulting from a delay in placement of sufficient time to preclude a union of the material in two successive lifts.

joint, construction

interface between two successive placements; bond is typically required at such joints and reinforcement may be continuous.

joint, contraction

formed, sawed, or tooled groove in a repair surface to create a weakened plane and regulate the location of cracking resulting from restrained dimensional change.

joint, control

see joint, contraction (preferred term.)

joint, expansion

1) a separation provided between adjoining parts of a structure to allow expansion and contraction; 2) a separation between pavement slabs on grade, filled with a compressible filler material.

joint, groove

see joint, contraction (preferred term).

joint, isolation

a separation between adjoining parts of a structure that allows relative movement in three directions; usually vertical planes located to avoid formation of cracks in the structure. (See also joint, contraction and joint, expansion.)

joint, longitudinal

a joint parallel to the length of a structure or pavement.

joint, sawed

a joint cut in hardened concrete, generally not to the full depth of the member, by means of special equipment.

joint, transverse

a joint normal to the longitudinal dimension of a structural element, assembly of elements, slab, or structure.

joint filler

compressible material used to fill a joint to prevent the infiltration of debris and to provide support for sealants.

joint sealant

joint spall

a fragment detached from a concrete mass adjacent to a joint.


a specially built mobile carrier used to provide a work platform for tunneling operations, such as installing rock bolts and grouting.

jurisdictional authority

person or entity that has legal control over the applicable building code and permitting procedures for a structure; examples of jurisdictional authorities include local building officials.

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- K -


a saw cut in a concrete surface for embedment of the perimeter of a membrane or other thin surface treatment.


—a recess or groove in a concrete substrate which is filled with repair material to provide increased shear strength along the interface.

- L -


a weak layer of cement and aggregate fines on a concrete surface that is usually caused by an overwet mixture, overworking the mixture or excessive finishing, underwater concrete placement, or combinations thereof.


to bond layers of a material.


equipment for shooting refractory shotcrete material into areas that have a high temperature; typically, a length of metal pipe with an extended nozzle with various configurations.


a stable emulsion of natural or synthetic rubber in water.

latex-modified concrete


the quantity of material that accidentally enters or escapes through an opening such as a hole or crack.

length change

increase or decrease in length. (See also volume change and deformation.)

licensed design professional

1) An engineer or architect who is licensed to practice structural design as defined by the statutory requirements of the professional licensing laws of a state (province) or jurisdiction; 2) The architect or engineer, licensed as described, who is responsible for the structural design of a particular project (also historically engineer of record).


individual layer of repair material where several layers or courses are required to achieve the total depth of a repair.

lift-off test

a procedure that uses a calibrated hydraulic ram system to assess the effective force in an unbonded post-tensioned tendon or to detension existing tendons.


softening and raising or wrinkling of a pervious coat by the application of an additional coat; often caused by coatings containing strong solvents.

linear polarization

a nondestructive testing method to estimate the instantaneous corrosion rate of the concrete reinforcement located below the test point by measuring the current required to change by a fixed amount the potential difference between the reinforcement and a standard reference electrode.


any protective material applied to the interior surface of a conduit, pipe, or tunnel to provide watertightness, erosion resistance, chemical resistance, or reduced friction.

liquid-volume measurement

measurement of grout on the basis of the total volume of solid and liquid constituents.

live load

a moving load on a structure.

load cell

device for measuring the magnitude of an applied load.

load factor

a factor by which a service load is multiplied to determine a factored load used in the strength-design method.

load test

procedure consisting of applying loads to verify the strength and behavior of a structure or structural member.


device that maintains tension on a monostrand tendon while the end anchorage is replaced.

longitudinal crack


a definite quantity of a product or material accumulated under conditions that are considered uniform for sampling purposes.

low-pressure spray-applied mortar

the placement of a repair material by spraying using a low- velocity pump with air added at the nozzle.

low-pressure water blasting


in grouting, the physico-chemical characteristic of a grout material flow through a soil or rock that is the inverse of the inherent friction of that material to the soil or rock; comparable to “wetness.”

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