| dc.description.abstract | Use of high performance concrete has tremendous potential for improving economy and long term durability of structures. The State of Oklahoma has an abundance of high quality aggregates that are necessary for the production of high strength/high performance (HSHPC) concrete . This research report is intended to help the state harness the economic advantages of constructing Oklahoma's infrastructure with HSHPC. The research program systematically examined locally available materials to determine those most suitable for production ofHSHPC in Oklahoma, and tested mixture designs to see the effects of interactions of those materials. The effects of changing cement source and type, fine aggregate grading, and coarse aggregate type and grading were studied. Concrete mixtures were tested where only a single material (for example, cement) was varied while all others were held constant. Materials included in the testing program were Type I, II, and III cements from various suppliers , fine aggregates with two different fineness moduli, and four types of coarse aggregates in two gradings. A study was then conducted to examine the effects of varying total cementitious materials content, addition of supplementary cementitious material (Class C fly ash), and varying water to cementitious material ratio on properties ofHSHPC. The research established that Oklahoma has outstanding locally available materials capable of producing HSHPC with compressive strengths of 100 MPa (14,000 psi) and greater. Several cements were found suitable, although some variations in concrete strength as a result of changing the cement were observed. Crushed limestone, rhyolite, and granite coarse aggregates all performed well in HSHPC; sandstone river gravel was only suitable for producing concretes with strengths up to about 70 MPa (10,000 psi). Exceeding a total cementitious material content of about 500 to 550 kg/m3 resulted in little to no additional strength benefit. Replacement of up to 20 percent of the portland cement with Class C fly ash reduced early strength, but improved workability and allowed use of a lower water to cementitious material ratio, effectively increasing long term compressive strength. | |
