ASTM C55 currently stipulates testing for linear drying shrinkage once every two years provided there is no change to ..materials, concrete mix design, manufacturing process, and curing method. At the current time, there are no such frequency requirements for compressive strength, absorption, and dimensional tolerances. This change proposes to add an annual testing frequency for compressive strength, absorption, density, and dimensional tolerances. The proposed time frame relates to the production date, since there are some specialty units that are produced, and may remain in inventory for over 1 year. Anchoring the time frame from production date does not trigger additional testing on these specialty units if they are not manufactured at least annually. Additionally, this ballot proposes to add language so that a change in configuration or dimension does not trigger additional testing. This language mirrors that already in ASTM C140 for lot, and allows for recognition that for many concrete masonry units, several configurations may be produced from the same batch, at the same time. Testing on all configurations is not necessary, so long as the other variables (mix design, materials, production and curing methods) do not change. NOTE identical language was added to ASTM C90 in a previous balloting cycle, so this change harmonizes C55 and C90.
Keywordsabsorption; compressive strength; concrete brick; concrete building brick; concrete masonry units; linear drying shrinkage; portland cement; Brick--specifications; Concrete construction materials/applications--specifications; Masonry units--specifications;