Potential Reuse of Electric-Arc Furnace Dust (EAFD) in Concrete

This study investigated electric arc furnace dust (EAFD) reuse as a raw material in concrete mixes. A comprehensive experimental program consisting of two phases of testing was carried out. The first phase included the replacement of ordinary Portland (Type I) cement by unsieved dust with the percentages of 0, 2.5, 5, 7.5 and 10%. The second phase included the replacement of quartz (filler) by sieved dust with the percentages of 0, 2.5, 5, 7.5 and 10%. Leaching tests were carried out to find out if arsenic, chromium and lead were contained in concrete. The study concluded that the workability of fresh concrete increased with increasing the percentage of used dust. The use of 2.5% dust resulted in concrete with similar compressive strength and acceptable splitting strength when compared to that of the standard mix. The concrete mixes containing sieved and unsieved EAFD were able to contain arsenic and chromium. Additionally, the concrete mixes containing sieved EAFD were able to contain lead

Probabilistic Based Design of FRP Structures

This thesis presents the results of an analytical probabilistic based design procedure for concentrically loaded compression members and simply supported beams of fiber-reinforced polymeric (FRP) composite materials. Resistance factors for use in an LRFD format are developed for columns for both flexural buckling and local buckling of doubly symmetric sections, both flexural buckling and flexural-torsional buckling of equal leg angles, and material failure. Resistance factors are developed for lateral-torsional buckling of simply supported doubly symmetric beams loaded with concentrated vertical loads at mid-spans. The developed resistance factors are a function of the coefficient of variation of the appropriate material properties. The proposed resistance factors were determined to provide a reliability index of 3.0 for stability failure modes and a reliability index of 3.5 for the material failure mode

Utilization of Cement Incorporated with Water Treatment Sludge

This study investigated the use of water treatment sludge to replace cement in the production of paving tiles for external use. The study utilized sludge-cement replacement percentages of 10%, 20%, 30%, 40% and 50%. Produced tiles were tested for water absorption and breaking (bending) strength. Leaching of sludge metals from tiles was assessed using TCLP. The study showed that all produced tiles exhibited a water absorption ratio of around 10%. The study concluded that produced tiles, except for 50% sludge-cement replacement, comply with the breaking strength requirements of 2.8 MPa for tiles for external use. The TCLP results indicated that metal leaching from tiles is negligible

Prediction of the Service Life of a Reinforced Concrete Column under Chloride Environment

In the present investigation, service life of a reinforced concrete column exposed to chloride environment has been predicted. This study has been based on numerical simulation of chloride ion diffusion in a concrete column during its anticipated life span. The simulation process has included the concrete cover replacement whenever chloride ion concentration has reached the critical threshold value at the reinforcement surface. Repair scheduling of the concrete column under consideration has been discussed. Effects of the concrete cover thickness and the water cement ratio on the service life of the concrete column at hand have been presented. A new approach for arranging locations of reinforcement steel bars has been introduced. This approach is intended to prolong the service life of the concrete column under consideration against chloride induced corrosion

COVID-19 and semen fluid parameters, a retrospective study from infertility clinics

The study of the effects of SARS-CoV-2 infection and/or vaccination on semen fluid analysis (SFA) parameters is still incomplete. The aim of this study is to assess the effect of COVID-19 infection and vaccination on sperm parameters for a sample of individuals visiting multi-infertility clinics in Jordan. SFA records were collected retrospectively between September and November 2021 and analyzed using Jamovi software (version 2.2.5 for Windows); p-values p = 0.04). It is concluded that SARS-CoV-2 infection and vaccines have no negative effects on SFA parameters. </p