Factors Affecting Performance of Unit Masonry Mortar


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Title: Factors Affecting Performance of Unit Masonry Mortar

Author(s): William L. Zemaitis

Publication: Journal Proceedings

Volume: 56

Issue: 12

Appears on pages(s): 461-472

Keywords: none

Date: 12/1/1959

Laboratory and field mortars, made according to ASTM C 270, were investigated for durability and then compared to determine whether taboratory tests could be used to check field durability. First, a laboratory investigation was made on durability of mortar mixtures using standard sand and two masonry cements meeting ASTM C 91 specifications, and using cement-lime-sand mixtures composed of eight different brands of limes. Three cement-lime-sand mixtures were investigated: 1;1;6, 1:1 1/4:6 a n d 1:2:9. Second, a field-mix investigation was made and it showed that about 13 percent entrained air was necessary to pro-tect Types 0 and K, ASTM C 270 combinations, against freezing and thawin for Types failure, and 11 percent was needed N . All cement-lime-sand combinations needed the addition of an air-entraining agent for durability. All masonry cement mixes were durable with-out the need of additional air-entraining agents. It was found that materials tested for durability in the laboratory with Ottawa sand at a flow of 1 10 *5 showed good re-lationship to their durability performance at an average field consistency (130 *5 flow). The field mixes used an ASTM median-graded field sand and a Field mixer.