Flexural strengthening of reinforced concrete beams using fabric reinforced Alkali-Activated Slag matrix

Old Reinforced Concrete (RC) buildings are facing different degrees of structural deterioration and require proper strengthening to enhance their structural performance as well as to extend their life span. Fabric reinforced Alkali-Activated Slag (AAS) matrix is proposed to strengthen RC beams in this study. Seven RC beams with and without strengthening were prepared and tested under four-point bending. Test results indicate that use of AAS matrix as replacement for conventional cement-based matrix can change the failure mode of the strengthened beams from end-debonding of strengthening layer to slippage combined with rupture of fabric. The AAS-based strengthening strategy is able to enhance the loading capacity and flexural stiffness of RC beams as well as to reduce the strain of tensile reinforcements. Except the specimens failed in the premature debonding, increasing the fabric amount in the strengthening scheme improves the loading capacity of beams. In an optimal case, the yielding and ultimate loads of the strengthened beams are enhanced by 22.2% and 26.4%, respectively. Moreover, an analytical model was developed to predict the characteristic loads of the fabric reinforced AAS matrix strengthened beams. It shows that the analytical model could overestimate the yielding and ultimate loads of the strengthened beams, probably due to slippage and reduced synergistic effect of fabric bundles in the strengthening system. Based on that, two efficiency factors of 0.35 and 0.25, taking account of the area of effective fabric, are obtained and recommended to estimate the yielding and ultimate loads of fabric reinforced AAS matrix-strengthened beams, respectively

Potential Utilization of RDF as an Alternative Fuel to be Used in Cement Industry in Jordan

This experimental research aimed to examine potential production and utilization of RDF derived from mixed municipal solid waste using bio-drying technology to be used as a substitute fuel for the traditional fuel currently used in cement plants in Jordan. The characteristics of RDF produced were identified and compared with limits and criteria set by some European countries. An economic model for RDF utilization in cement industry was created. The model proposes six different options resulting from adding RDF as a substitute fuel for the petcoke fuel currently used. A cost analysis for each option proposed was performed to estimate the economic and environmental savings of RDF utilization in cement industry. At the end of the bio-drying process, the mass of dried waste directed to the landfill was reduced by about 35%. In the case of the recovery of RDF materials from dried waste, the mass of waste to be landfilled was reduced by 69%. The bio-drying process allowed an increase in the heating value of waste (LHV) by 58% to reach 15.58 MJ/kg, as a result of the reduction of waste moisture. RDF produced had high calorific value, low water content, and satisfactory chlorine content. With regard to the concentration of the heavy metals, all of the RDF samples tested had lower concentrations than those values set by some European countries. The findings showed that adding 15% RDF as a substitute fuel, equaling 4.92 tons/h, to the fuel used in cement kilns will save 486 USD/h in petcoke costs, with 2.27 tons/h of CO2 being emitted into the atmosphere at a net saving of 389 USD/h