Special-Uses-Alkali - Expanded Shale & Clay

metakaolin, an 8% replacement of cement with metakaolin, and a control. The 8% addition ofmetakaolin to the concrete mix increased the compressive strength, on average, by 34% at allages. The 8% replacement of cement by metakaolin resulted in an average compressive strengthincrease of 28% at all ages. Compressive strength measurements can be found below in Table 1.Testing Age(days)Table 1. MetaMax compressive strength results.Control (psi)8% addition ofMetaMax (psi)Replacement ofcement by 8%MetaMax (psi)7 8600 11600 1060028 10000 13700 1250056 11300 15200 1370090 12200 16500 16400180 13000 17300 17300365 14100 18500 18700Concrete’s ability to resist chloride ion penetration testing (AASHTO T 277-89) was performedon the same additions and replacements of metakaolin in the concrete. The charge passed, incoulombs, by the control was 1800, while the 8% addition of metakaolin passed 900 coulombs,and the concrete with 8% cement replacement by metakaolin passed 1000 coulombs. Accordingto the relevant AASHTO standard, the chloride ion permeability is very low when passing 100to1000 coulombs, the permeability is low when passing 1000 to 2000 coulombs.2.2.3. Thiele Kaolin CompanyThiele Kaolin Company in Sandersville Georgia manufactures a calcined kaolinite calledKAOROCK which was supplied to the Civil Engineering Department of Georgia Institute ofTechnology to research the benefits of metakaolin over silica fume.Georgia Institute of Technology performed compressive strength, splitting tensile strength,flexural strength (modulus of rupture), rapid chloride permeability (ASTM C 1202), sulfateresistance (ASTM C 1012), and ASR testing (ASTM C 1260). The compressive strength,splitting tensile strength, and flexural strength, and rapid chloride permeability tests were all8