Length Change Apparatus

Length Change Apparatus measures changes in length of cast prisms due to alkali-silica reactivity (ASR), autoclave curing and other causes not related to applied load. Methods are applicable to testing of hardened portland cement paste, mortar, concrete, or evaluation of hydraulic hydrated lime for structural purposes.


Cement Autoclave
Model: HM-252
Length Comparator

Length Comparator

Starting at $840.00
Models: HM-250D, HM-250
2-Gang Prism Molds, 1x1x10in

2-Gang Prism Molds, 1x1x10in

Starting at $133.00
Models: HM-257, HM-258
Single Prism Mold, 3x3x10in
Model: HM-259
2-Gang Prism Mold, 2x2x10in
Model: HM-255
Single Prism Mold, 1x1x10in
Model: HM-256

HM-254 Test Bar Holder (order separately) holds up to eight 1x1in (25x25mm) bars of 10in (254mm) gage length. Bars are held vertically above water level to expose all specimens to Autoclave steam.

Prism Molds, Gage Studs (ASTM C 490, AASHTO M 210, others): Prism Molds are corrosion- resistant steel (HM-258 is stainless) with base plate, removable partitions and end plates, designed to provide required length of 10in (254mm) between ends of gage studs cast in ends of bars. Dimensions from outside ends of studs (comparator gage contact points) are 11-5/8in (296mm); specimens are 11-1/4in (286mm) long.

Select molds for specimen cross sections of 1x1in, 2x2in, or 3x3in. Molds for 5in (127mm) gage length specimens available. Package of ten stainless steel Gage Studs HM-268 are knurled and threaded, 1/4x13/16in (6.35x20.64mm) diameter x L.

HM-270 Mortar Bar Container (ASTM C 227), is stainless steel with tight fitting cover to seal in water vapor. Vertically supports up to 36 mortar bars in container with lower end above water surface. Box is 9x11x15.5in (229x279x394mm), LxWxH.

  • Cement Autoclave is ASME certified. Used in curing of mortar bar specimens for determining expansion of hydraulic cements in compliance with ASTM C151 and AASHTO T 107M.
  • Length Comparator with dial or digital indicator offers precise measurement of length changes in accordance with ASM and AASHTO standards. Can test specimens up to 4x4x10in.
  • 2-Gang Prism Molds, 1x1x10in available in corrosion-resistant steel or stainless steel models. Used for casting mortar, concrete or Portland cement paste specimens.
  • Single Prism Mold, 3x3x10in is made of corrosion-resistant steel and used in length change testing of different concrete specimens.
  • 2-Gang Prism Mold, 2x2x10in for length change testing of Portland cement paste, concrete or mortar specimens. Can also be used with length comparator for measuring change in cast prisms due to alkali-silica reactivity and other causes.
  • Mortar Bar Container for Length Gauge Test designed to support up to 36 mortar bars in length gauge testing.
  • Single Prism Mold, 1x1x10in is a corrosion-resistant steel mold used in length change testing of mortar, concrete or Portland cement paste samples.