STR-894: BOND STRENGTH OF RIBBED-SURFACE HIGH-MODULUS GLASS FRP BARS EMBEDDED INTO UNCONFINED UHPFRC

High-modulus (HM) ribbed-surface glass fiber reinforced polymer (GFRP) bars have recently been used in concrete bridge decks to avoid corrosion of steel reinforcement resulting from the use of de-icing salts in winter times in North America. Recently, prefabricated full-depth deck panels (FDDPs), made of normal strength concrete or high performance concrete and reinforced with GFRP bars, are used in Canada to acceleration bridge construction. The FDDPs are connected through panel-to-panel and panel-to-girder connections. These connections are filled with joint-filled cementitious materials as ultra-high performance fiber-reinforced concrete (UHPFRC). This paper presents the experimental program to investigate the bond strength of the GFRP bars embedded into unconfined UHPFRC using pull-out testing, leading to the proper GFRP bar development length required to determine the width of the closure strip between connected slabs. The longitudinal GFRP/UHPFRC interface is influenced by (i) the development length-to-nominal diameter of the bar ratio, (ii) the concrete cover-to-bar diameter ratio and (iii) the development length-to-embedment depth ratio due to lugs or headed-end and (iv) concrete compressive strength. GFRP bars embedded into UHPFRC would rely less on the friction and adhesion of the interface, and more on the bearing of the lugs against the concrete. These bearing forces act at an angle to the axis of the bar, causing radial outward forces. Pullout failure of the GFRP/UHPFRC interface leads to shearing of the lugs and bar slippage from the headed-end. Adequate bond strength between the GFRP/UHPFRC interfaces is necessary for design of jointed PDDFs. Therefore, accurate predictions of development length and bond strength of straight or headed-end bars without passing through the high localized stresses due to flexural are essential for safe design

STR-831: FATIGUE STRENGTH OF ANGLE-SHAPED TRANSVERSE CONNECTION FOR GFRP-REINFORCED PRECAST FULL-DEPTH DECK PANELS IN ACCELERATED BRIDGE CONSTRUCTION

Prefabricated bridges elements and systems (PBES) are subjected to repeated truck loads while being exposed to weather conditions. Fatigue of the structural elements and corrosion of the reinforcement are the main reasons for bridge deterioration. This research investigates the fatigue strength of full-depth deck panels (FDDP) resting over steel cross-braced girders and reinforced with ribbed-surface, high-modulus (HM), glass fiber reinforced polymer (GFRP) bars. The precast FDDP has transverse panel-to-panel connection of angle-shape with female shear key, and panel-to-girder connection of V-shape, where both connections are filled with ultra-high performance fiber reinforced concrete (UHPFRC). Two different fatigue loading were conducted to simulate the Canadian Highway Bridge Design Code (CHBDC) truck loading, namely: constant amplitude fatigue (CAF) loading and variable amplitude fatigue (VAF) loading. The fatigue damage for all cycles is summed to obtain the cumulative fatigue damage (CFD) for the entire loading history. The reliability of the GFRP-reinforced precast FDDP subjected to high cycle fatigue is then evaluated based on load-cycle (P-N) damage accumulation approach. A simple life-span prediction model is proposed for the FDDP based on the CFD

STR-832: ULTIMATE FLEXURAL STRENGTH AND LONG-TERM CREEP DEFLECTION FOR STRUCTURAL INSULATED FOAM-TIMBER SANDWICH PANELS

The structural insulated panel (SIP) is a sandwich structured composite that is prefabricated by attaching a lightweight thick core made of Expanded Polystyrene (EPS) foam laminated between two thin, and stiff face skins made of Oriented Strand Board (OSB). The use of sandwich panels provides key benefits over conventional materials including: very low weight; high stiffness; durability and; production and construction cost savings. The facing skins of the sandwich panel can be considered as the flanges for the I-beam carrying bending stresses in which one face skin is subjected to tension, and the other is in compression. The core resists the shear loads and stabilizes the skin faces together giving uniformly stiffened panel. OSB is wood product that shrinks when dry and swells when adsorb moisture either due to liquid or vapor from the surrounding atmosphere. The relative combination of relative humidity and temperature is introduced into the equilibrium moisture content (EMC) that increases with the increase of the relative humidity and with decreasing temperature. Experimental test matrix includes testing 2.44 m (8’) and 4.88 m (16’) long SIPs for 5 years under different sustained loads and weather resistive barriers (WRBs), recording creep deflection, relative humidity and temperature. After creep recovery, the SIPs are loaded to-collapse to determine their flexural strength

MAT-702: MECHANICAL BEHAVIOUR OF ULTRA-HIGH PERFORMANCE CONCRETE OBTAINED WITH DIFFERENT CONCRETE CONSTITUENTS AND MIX DESIGNS

This research investigates the mechanical behaviour for the Ultra-High Performance Concrete (UHPC) and UltraHigh Performance Fiber Reinforced Concrete (UHPFRC). UHPC and UHPFRC are designed to be self-consolidated concrete that level itself without mechanical vibration due to its highly flowability and moderate viscosity. UHPFRC is used as joint-fill cementitious materials for the connections of prefabricated bride elements and systems used for the Accelerated Bridge Construction and rapid bridge replacement. The main concrete constituents of such materials consist from: binders (cement), powders (fillers), liquids (additives), water, and fibers. Hence, the mixture proportion design should follow a densified mixture design algorithm to densify the particle packing that reduces the amount of pores and reduces the water/binder ratio to attain the design criteria. The concrete mix design has two approaches, namely: classical mixture including the response surface methodology and factorial-based central composite design, also known as the mathematically independent variable. Experimental work is conducted to determine the optimum particle size distribution and to identify the chemical effects followed by parametric experimental tests on different concrete constituents to develop series of UHPC/UHPFRC products and monitor there rheological behavior

Multislice CT in sinonasal polypi; Functional endoscopic sinus surgery correlation

Background: Nasal and sinus illnesses are diagnosed with computed tomography (CT) because CT scans effectively bone anatomy is depicted with air spaces, opacified sinuses, and detailed structural details. Objective: The significance of using multislice CT for the detection and characterization of sinus polyps and the relationship between the CT findings and those of functional endoscopic sinus surgery (FESS) have been studied. Patients and Methods: At Zagazig University's Radiodiagnosis Department, we conducted this study on 18 patients, 10 of which were females and eight were males, from a total of 33 individuals. To emphasize the role of multislice (CT) in diagnosis and characterization of sinonasal polypi during functional endoscopic sinus surgery, numerous CT parameters were used and correlated with operational findings. Results: There was a strong correlation calculated by Spearman correlation coefficient (r) for right-sided and left-sided surgeries of 0.76 and 0.87, respectively, for operative endoscopic and Lund-Mackay staging scores. Conclusion: Based on functional endoscopic sinus results, CT and diagnostic endoscopy may be the new standard of care in the diagnosis of sinonasal diseases

Study The Response of Two Faba Bean Cultivars to Mineral and Bio-Phosphorus Fertilization

Reliance on vegetable protein sources has become an urgent necessity in Egypt due to the high prices of animal protein sources. This research was conducted to study the effect of different rates of mineral phosphate fertilizer with some phosphorous bio-fertilizers (Phosphorine and Microbene) on the productivity and quality of two faba bean cultivars Giza 843 and Masr3 in 2018/2019 and 2019/2020 winter seasons. The results revealed that a significant improvement could be found for most studied traits by the application of 30 kg P2O5/fad of phosphate fertilizer. Moreover, Phosphorine as a bio-fertilizer exhibited a significant enhancement on all studied traits, except shelling% and straw yield in the second season. The cultivars exerted different responses to the rates of phosphate fertilization for plant height, shelling% and protein content in the 2018/2019 season; number of branches/plant and 100 seed weight in the 2019/2020 season; as well as a noticeable response in seed and straw yields/fad, husk, and protein percentages in the two seasons. The interaction between cultivars and bio-fertilizers was significant for seeds protein and carbohydrates content in the 2019/2020 season. Furthermore, phosphate fertilizer rates and bi-fertilizers interaction gave a significant influence on seed yield/fad in both seasons and straw yield/fad in the first season. The second order interaction i.e., cultivars × phosphate × bio-fertilizers possessed a significant effect for seed and straw yields/fad, where the highest seed and straw yields were obtained from Masr1 cultivar when received 30 kg P2O5/fad and inoculated with Phosphorine biofertilizer in both seasons