Experimental study on recycled steel fiber concrete
Some basic properties of recycled steel fiber aggregate were tested, such as surface features, water absorption, apparent ensity, crushing index, cube compressive strength and so on. Recycled steel fiber aggregate were used to replace the natural aggregate by 0%, 25%, 50% and 100% proportion to make concrete. Afterward, compressive strength, splitting tensile strength and flexural strength were investigated at ages 3, 7 and 28 days. The results showed that thorn appearance of recycled steel fiber aggregate makes packing density decrease, crushing value and absorption increase. The compressive strength, splitting tensile strength and flexural strength of the recycled concrete depend on the mix proportions. Generally, the strength of recycled concrete can be 15–25% lower than that of concrete made with virgin aggregate.
Pro-Ecological Utilization of Crushed Concrete as an Aggregate to Improve the Compressive Strength with Steel Fibers and Styrene-Butadiene Rubber Latex
Demolition of old structures and pro-ecological utilisation of such demolished concrete waste materials must be considered an important ecological issue that helps conserve non-renewable natural resources. Crushed concrete in the form of recycled coarse aggregate (RCA), steel fibres (SF) of 30–50 kg/m3 and styrene-butadiene rubber (SBR) latex of 5%, 10%, and 15% by cement weight attempted to strengthen the strength in compression of polymer modified steel fiber reinforced crushed concrete (PMSFRCC). Ninety-nine cubes each of M20, M25, M30, and M40 grade were cast separately to assess the strength in compression of natural aggregate concrete (NAC), crushed concrete (CC), and PMSFRCC. According to the experimental results, PMSFRCC with SF 30 kg/m3 and SBR Latex 5% by weight of cement improves compressive strength by 8.92% & 6.22% in mix-1, 7.63% & 5.45% in mix-2, 4.27% & 7.87% in mix-3, and 9.87% & 7.46% in mix-4 when compared to NAC at 28 and 90 days.It reflects significant improvement and validation of utilisation of CC as a potential source of an aggregate to improve compressive strength for the desired purpose.
Selected Ethical Issues in Research and Publication: Perceptions of Health Education Faculty
A national random sample of 195 university health education faculty at graduate degree–granting programs completed a 31-item survey with regard to their perceptions of ethical issues in research and publishing. Most respondents were male (57%), tenured (75%), had graduate faculty status (92%), had presented original research at conferences (85%), and had published articles in health education journals (89%). Faculty members were requested to assess whether 21 scenarios dealing with ethical issues in research and publishing were ethical, unethical, questionable, or not an ethical issue. Of the scenarios, 3 were considered ethical and 7 unethical by the majority of respondents. The perceptions of how ethical the remaining 11 scenarios were varied considerably. Perceptions of the ethical scenarios did not differ among respondents by sex, academic rank, years taught as a faculty member, whether the department taught units/classes on research ethics, or whether the respondents were from doctoral-level versus master’s-level programs.