Results 1 - 3 of 3
Results 1 - 3 of 3. Search took: 0.018 seconds
|Sort by: date | relevance|
[en] Sulphate expansion and strength tests were performed on mortars containing equal proportions of Type 10 (ASTM Type I) Portland cement and fly ash as the cementitious material. Two intermediate-Ca subbituminous ashes, one high-Ca subbituminous ash and one bituminous ash were tested. Control mortars manufactured with Types 10 and Type 50 (Type V ASTM) cements and one mortar containing 50% replacement of cement with limestone powder were also examined. The period and temperature of curing prior to sulphate exposure and the concentration and pH of the attacking solutions were other test parameters. Results indicate that the two intermediate-Ca subbituminous ashes from Alberta Canada, combined with Type 10 cement produce mortars that show excellent long-term strength, acceptable short term strength, and are highly resistant to attack by aggressive sulphate solutions. In some cases durability of these mortars was better than the control mortar made with Type 50 cement. On the other hand, mortar made using the high-Ca ash showed very high susceptibility to sulphate attack; at the same time, mortars made with this ash showed good strength development. Qualitative x-ray diffraction analysis indicates the presence of more lime, magnesium and iron bearing crystalline compounds in the high-Ca ash than in the Alberta ashes. These appear to be responsible for the poor performance in sulphate environments
[en] The photon detection efficiency (PDE) and response linearity of Multi-Pixel Photon Counter (MPPC) is presented at 470 and at 500 nm coupled with wavelength shifting fibre. It is found that crosstalk and after-pulse increase artificially the PDE as much as 30% (relative). PDE increase with gain is found to be 2.5%/105. An empirical fit based on simple statistical assumptions is being developed and allows for some prediction of the fraction of nuisance parameters in the linearity response although experimental conditions are not completely modelled and are in the process of being tuned using a Monte Carlo simulation.