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KANSAS
CITY DISTRICT AGGREGATE PROGRAM
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 The purpose of these installations was to provide field durability data on concrete specimens containing certain aggregate materials pro-duced commercially in the Kansas City District, CE. This work is a part of an aggregate program being conducted by the Kansas City District. First Installation In January 1958, 18 concrete beams (6- by 6- by 30-in.) were installed at half-tide elevation. The beams represented six different combinations of fine and coarse aggregate (three beams per combination). The concrete mixtures used contained Type II low-alkali cement and an air-entraining admixture, and were designed to have a water-cement ratio (w/c) of 5.0 gal per bag, a slump of 2 to 3 in., an air content of 4 to 7 percent, and a maximum aggregate size of 1½ in. The mixtures all contained Type II cement and an air-entraining admixture and were designed to have a cement factor of approximately 6 bag per cu yd, a slump of 2 to 3 in., and an air content of approximately 4½ percent. Second Installation In May 1959, 18 concrete beams (6- by 6- by 30-in.) were installed at half-tide elevation. |
These beams also represented six different combinations of fine and coarse aggregate. The concrete mixtures contained Type II cement and an air-entraining admixture, with the other characteristics such as w/-c, slump, air content, and aggregate size being the same as in the 1958 beams. Third Installation In November 1962, nine concrete beams (6- by 6- by 30-in.) were installed at half-tide elevation. These beams represented three different concrete mix-tures (three beams per mixture). The concrete mixtures were identical with those used for the concrete beams installed in 1958 except for fine and coarse aggregates and the replacement in one mixture of a portion of the cement with a fly ash. Fourth Installation In December 1963, nine concrete beams (6- by 6- by 30-in.) were installed on the Treat Island exposure rack at half-tide elevation. These beams repre-sented three concrete mixtures (three beams per mixture). Two of the mixtures had a maximum aggregate size of 1½ in., and one of these mixtures contained a cement-replacement material. The third mixture had a ¾-in. maximum aggregate size. The mixture with a maximum aggregate size of ¾ in. (gravel) was not durable in this exposure. The other two mixtures (fly ash plus sand E plus limestone; sand G plus quartzite) were much more durable. |
Fifth Installation In May 1969, three concrete beams (6- by 6- by 30-in.) were installed at half-tide elevation. The beams represented three concrete batches (one beam per batch). The concrete mixture was air entrained and contained Type II low-alkali portland cement and a cement-replacement material (20 percent fly ash by absolute volume); the mixture was designed to have a cement factor of 5.76 bag per cu yd, a slump of 2½ in., and an air content of 4.7 to 5.0 percent. Crushed limestone (1½-in. maximum size) was the aggregate. The compressive strength of this mixture at 28-days age was approximately 3,350 psi. Sixth Installation In July 1974, six concrete beams (6- by 6- by 30-in.) representing two con-crete batches (three beams per mixture) were installed at half-tide level. The concrete mixtures (20 and 21) contained Type II cement and an air-entraining admixture and were designed to have cement factors of 5.3 and 5.7 bags per cu yd, slumps of 2½ and 2 in., and air contents of 5 and 4.5 percent. Maximum aggregate sizes were 1½ in. Mixture 20 contained a cement-replacement material. Tables give exposure records and other pertinent data on these beams. |