Laserfiche WebLink
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />3. Materials Testing - Physical tests for gradation, specific <br />gravity, absorption, sodium sulfate soundness, L.A. abrasion, organic <br />impurities, clay and friable lumps and alkali activity were performed <br />on the potential RCC aggregate material from the alluvial deposits. <br />The natural gradation of the sample showed the material to be fairly <br />well graded but considerably finer than the recommended gradation for <br />RCC. This would indicate that at least some amount of processing of <br />the material will be necessary before it is suitable as RCC aggregate. <br />In addition the specific gravity of the material was lower than ex- <br />pected and the absorption higher. Both the sodium sulfate soundness <br />and L.A. abrasion tests showed the durability of the aggregate to be <br />suspect. In addition the results of the test for clay lumps and fri- <br />able material far exceeded acceptable values for concrete aggregate. <br />All of the tests results, therefore, except organic impurities and <br />potential reactivity reflected negatively on the suitability of the <br />material as RCC aggregate. <br /> <br />An RCC trial mix program was developed using the pit run material as <br />aggregate with cement contents of 125 1bs/cu. yd., 175 1bs/cu. yd. and <br />225 1bs/cu. yd. The compressive strength results from these trials <br />were uniformly low regardless of cement content and age. It was sus- <br />pected that the cement used in the trials was defective and this was <br />confirmed by laboratory tests. A new set of cylinders was made with <br />175 1bs/cu. yd. cement content. The compressive strength results from <br />these cylinders are higher than the previous trials but do not show <br />typical strength gain for RCC. Laboratory test results and results of <br />the RCC trial mixes are included in Appendix C-1. <br /> <br />Mr. Ernest H. Schrader, Concrete Specialist and special consultant to <br />MKE on roller compacted concrete reviewed the available data on the <br />Rock Creek aggregate, examined a small sample and performed some of his <br />own tests on the aggregate material. Results of some of Mr. Schrader's <br />tests, most notably the absorption, differed from other reported re- <br />sults. Mr. Scharader's opinion, based on examination of a small sam- <br />ple, is that acceptable quality RCC aggregate, with proper processing, <br /> <br />3 - 12 <br /> <br />6819W/502OW <br />