Papers by Mahmoud SAYED AHMED
10th International Conference on Short and Medium Span Bridges, 2018
Three precast full depth deck panels (FDDP) reinforced with glass fiber reinforced polymers (GFRP... more Three precast full depth deck panels (FDDP) reinforced with glass fiber reinforced polymers (GFRP) bars were tested to collapse to investigate their punching shear strength. Precast FDDP segments were transversely connected to other ones, jointed with ultra-high performance fiber reinforced concrete (UHPFRC) and resting over steel twin girders. The ultimate load-to-collapse was placed in the mid transverse span, at the edge of the FDDP and eccentric to the transverse UHPFRC joint. The load has the Canadian truck CL625 wheel footprint of 250x600 mm. The experimental results determined the ultimate load, failure modes, and inclination of the punching crack and the critical punching sections. This research also resulted into analytical derivation for the punching shear that accounts for the two-way GFRP-reinforcement ratios, effective slab depth in combination with the observed critical area. Good correlations between predicted and experimental results have been achieved.
10th International Conference on Short and Medium Span Bridges, 2018
The Canadian Highway Bridge Design Code of 2014 specifies values applied loads on bridge railing ... more The Canadian Highway Bridge Design Code of 2014 specifies values applied loads on bridge railing to determine the applied moment and tension force for the design of the deck slab cantilever. However, these moment and tensile force values are as yet unavailable. This research investigates the geometrical variables and load locations effect on the structural performance of the edge stiffened cantilever slab, which are subjected to horizontal line load. Finite Element Modeling software was utilized to conduct linear elastic analysis of concrete barrier rigidly connected to deck slab cantilevers. The geometrical properties include the linearly varying slab thickness, the transverse cantilever length, the longitudinal barrier length, and the varying wall thickness. Edge and mid-span loading at variable heights were determined based on the type of the barriers. Three-dimensional finite element models were constructed to extract design data for the shear and moment values for the wall, and tensile force and moment for the cantilever slab. Design data were analyzed using nonlinear regression analysis to provide simplified expressions, which can be used to determine the factored forces and moments needed for the structural design of the bridge barrier-deck joint as well as the deck slab cantilever due to vehicle impact forces.
Journal of Structures and Buildings, 2020
Fibre-reinforced polymer bars are rapidly becoming an approved alternative to conventional reinfo... more Fibre-reinforced polymer bars are rapidly becoming an approved alternative to conventional reinforcing steel bars, especially for severely exposed structures such as bridges. This paper reports on an experimental study on the bond characteristics of both sand-coated and ribbed-surface glass-fibre-reinforced polymer bars embedded in high-strength concrete (HSC). A total of 145 pull-out tests were conducted to examine the effect of varying parameters on the bond characteristics, namely embedment length, bar diameter, surface treatment and concrete cover. In addition, 45 pullout tests were conducted to investigate the effect of providing headed-end anchorage for the sand-coated bars. The experimental results showed that the sand-coated bars exhibited better bond strength than the ribbed-surface bars, which entailed lower development lengths. Thus, based on the experimental results, expressions for the development length of both sand-coated and ribbed-surface bars embedded in HSC were developed and compared against the results of formulae in available design standards. The comparison revealed that ACI 440-1R-06 produced lower conservative results than CAN/CSA S806-12.
The Fiber Reinforced Polymer (FRP) combines the reinforcement fibers of glass or other materials ... more The Fiber Reinforced Polymer (FRP) combines the reinforcement fibers of glass or other materials with thermoset and/or thermoplastic resins to form the composite FRP rebar. The pultruded thermoplastic composite rebar could be heated and remolded to be reformed and reshaped to suit specific design need. This is not possible with thermosetting resins. Thermoplastic composite has two major advantages; the first is the increase of impact resistance, and the second is being recyclable at the end of its service life. Experiments were conducted over three developed thermoplastic Glass FRP rebars with different diameters of 10 mm, 15 mm and 20 mm to determine their ultimate tensile strength (UTS). The 15 mm bar underwent the conditioned tensile loading in alkaline solution under 60oC during 90 days. The 10 mm bar underwent two levels of creep-deformation tests at 20% and 40% UTS for 816 hours. Result revels average tensile strength above 1000 MPa with tensile modulus of 62.5 GPa, insignificant creep strain along test duration, and strength retention of 90% while modulus retention is 100%.
The newly developed GFRP bar Number #3 (10 mm) passed three testing procedures named: (i) ultimat... more The newly developed GFRP bar Number #3 (10 mm) passed three testing procedures named: (i) ultimate tensile strength (UTS); (ii) creep rupture strength; and (iii) long-term creep loading. The bar #3 has an average value of 1016 MPa and 74.1 GPa for the ultimate stress and tensile modulus respectively. The creep rupture results obtained at stress ratio of 95%, 90%, 80% and 75% of the UTS. The creep rupture strength 106 hours was found to be about 49%. This value is above the specified limit value of 35% of UTS for the GFRP as set by design standard. Long-term creep tests were performed under two level of sustained tensile stress equivalent to 20% and 40% of the UTS of the bar up to 1670 hours. The tensile strain for bar subjected to 20% of UTS was 3.9 to 6.9% of the initial strain, while it ranged from 6.6 to 11.2% for bar loaded at 40% UTS. Creep data were analyzed and mathematically modeled.
Recent development of newly composite glass fiber reinforced polymers (GFRP) resulted into a prod... more Recent development of newly composite glass fiber reinforced polymers (GFRP) resulted into a production of newly straight and bent bars. GFRP bar is corrosion resistant reinforcing bar, is used to encounter the corrosion of the steel reinforcement. The GFRP bars are manufactured using highly resistant glass fibres embedded in a vinyl ester resin. The GFRP bars have a continuously profiled surface. The three developed straight GFRP bars with different diameters of 15 mm, 20 mm, and 25 mm are classified as the third generation (GIII) bars where their modulus of elasticity exceeds the 60 GPa. Pullout experiments for 15 mm, 20 mm, 25 mm straight bars were 4 times the bar diameter embedded into unconfined normal strength concrete blocks were conducted to determine the bond strength. Bond strength of straight bars results were more than 3 times the minimum bond strength required by design codes. The developed 15M deformed-bent bars exhibit high retention strength in the bent-to-straight portions of the stirrup while tested into confined concrete blocks.
To accelerate bridge construction, precast full-depth deck panels (FDDPs) are placed over steel g... more To accelerate bridge construction, precast full-depth deck panels (FDDPs) are placed over steel girders with transverse joints. In this paper, a transverse angle-joint is proposed with female shear key and bottom tongue. The joint has projecting glass fibre reinforced polymer (GFRP) bars from the precast panels and is filled with ultra-high performance fibre reinforced concrete (UHPFRC). Ultimate static, constant fatigue and variable fatigue load tests were performed under truck wheel footprint showed good results.
This research investigates the mechanical behaviour for the Ultra-High Performance Concrete (UHPC... more This research investigates the mechanical behaviour for the Ultra-High Performance Concrete (UHPC) and Ultra-High 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.
High-modulus (HM) ribbed-surface glass fiber reinforced polymer (GFRP) bars have recently been us... more 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
Prefabricated bridges elements and systems (PBES) are subjected to repeated truck loads while bei... more 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.
The First International Symposium on Jointless & Sustainable Bridges
The structural insulated panel (SIP) is a sandwich structured composite that is prefabricated by ... more 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.
This paper presents the use of full-depth, full-width precast deck panels (FDDPs) in accelerating... more This paper presents the use of full-depth, full-width precast deck panels (FDDPs) in accelerating the construction of integral as well as semi-abutment bridges. The superstructure is composed of steel I-girders with precast FDDPs. Precast FDDPs are recommended over cast-in-place (CIP) decks, as semi-integral abutment bridges allow movement due to elastic shortening, short term creep and shrinkage that take place before CIP deck is made integral with the approach slab. In this paper, precast FDDPs were constructed by normal strength concrete (NSM) and reinforced with ribbed-surface high modulus glass fiber reinforced polymer (GFRP) bars. The panel-to-girder and the transverse panel-to-panel connections were joint-filled with ultra-high performance fiber-reinforced concrete (UHPFRC). Three female panel-to-panel joints named Angle-Shape, C-Shape, and Zigzag-Shape were loaded eccentrically to the joint at the mid-span of the precast FDDP under simulated wheel truck loading to determine the joint ultimate strength. This paper pays attention to the precast joint at the deck slab-abutment to transverse the negative moment resulting from gravity loading and soil pressure. Experimental results of the pullout strength of GFRP bars embedded in UHPFRC joint are presented to assist in the determination of the proper joint width and associated GFRP bar development length into the joint to ensure full capacity of the bar at splice location.
The First International Symposium on Jointless & Sustainable Bridges
There is a growing need for durable and resilient prefabricated bridge systems which facilitate r... more There is a growing need for durable and resilient prefabricated bridge systems which facilitate rapid completion of on-site activities in order to minimize the impact on the travelling public. Prefabricated bridges can provide higher quality, accelerated, and safer construction. However, greater offsite prefabrications of bridge components necessitates an increased reliance on the long-term performance of field-installed connections between these components. Integral abutment bridges can be built by assembling precast concrete elements in site using mechanical joints filled with durable materials that prevent water leakage. Those precast elements include prefabricated pretensioned girders, deck slabs, abutment walls, wing walls and concrete or helical steel piles. Of particular interest here is the ultra-high performance fibre-reinforced concrete (UHPFRC) that can exhibit exceptional bond when cast against previously cast concrete and can significantly shorten the development length of embedded discrete glass fiber reinforced polymer (GFRP) bars. With the recent innovations in bridge infrastructure replacement, the use of UHPC in closure strips between precast concrete bridge segments became the main focus of bridge owners for its superior strength and durability. To increase competitiveness in supplying UHPC to bridge owners in Canada, this collaborative research with the industry is looking into an innovative UHPC design that combines both high concrete compressive strength, and enhanced durability and rheology. It is essential to produce design standards and performance-based specifications of UHPC through experimental trial and errors due to lack of reliable information in this subject in the related standards and literature. This research investigates different UHPC mixes designed to reach the desired strength and rheology. While UHPC materials clearly outperform conventional concrete in mechanical and durability performance, their production is proprietary and the development of economically competitive alternatives is warranted. Throughout this research, the desired fresh and hardened concrete properties as well as practical mixing procedure were achieved and reported herein. The UHPC’s material consists of combined from Ordinary Portland Cement (OPC), Silica Fume (SF), Fine Aggregate (FA), High Range Water Reducer (HRWR), regular water, and steel fiber reinforcement (SFR). The unique concrete mix design (CMD) relies on three main factors, namely: (i) the ratios of the cementitious materials to the fine aggregates; (ii) the optimum densified Particle Packing obtained from the particle size distribution (PSD); and (iii) the dosage rate for the admixtures while reducing the water to cementitious ratio. The concrete mixing constituents are designed to achieve higher compressive strength in 96 hours under the conventional curing regime. Experimental results include mixing ratios, procedures, time, compressive strength values, air voids in the system, flow diameter. Future applications in integral abutment bridge construction, incorporating the developed UHPFRC will be discussed.
ICSGE14: The 14th International Conference on Structural & Geotechnical Engineering 2015
This paper investigates the fatigue resistance of precast full-depth deck panels (FDDP) built wit... more This paper investigates the fatigue resistance of precast full-depth deck panels (FDDP) built with new construction materials and connection details. FDDP is constructed with normal strength concrete (NSC) and reinforced with high modulus (HM) glass fiber reinforced polymer (GFRP) ribbed bars. The panel-to-girder connections adopt the use of shear pockets to accommodate clustered shear studs welded to the supporting steel girders. The transverse panel-to-panel connection was developed forming two different female-to-female joint shapes (CZ-shapes) with 175-mm projecting GFRP bars from the FDDP, and female vertical shear key and closure strip filled with cementitious materials. The ultra-high performance fiber reinforced concrete (UHPFRC) was used to joint-fill the 200-mm transverse joint and the shear pockets. Two identical full-scale FDDPs for each type of the developed joints were erected to perform fatigue tests under the foot print of the Canadian Highway Bridge Design Code (CHBDC) truck wheel loading. The deck panel had 200-mm thickness, 2500-mm width and 3700-mm length in the direction of traffic and rest over braced steel twin-girders. Two types of fatigue tests were performed, namely: (i) incremental variable amplitude fatigue (VAF) loading; and (ii) constant amplitude fatigue (CAF) loading, followed by monotonically loaded the slab ultimate-to-collapse. Fatigue test results showed that the ultimate capacity of the slab under VAF loading, and/or after 4 million cycles of CAF exceeds the factored design wheel load specified into the CHBDC.
Precast full-depth deck panels (FDDP) with transverse joints, placed over steel or concrete girde... more Precast full-depth deck panels (FDDP) with transverse joints, placed over steel or concrete girders, are efficient in rapid bridge replacement. In this system, grouted pockets are provided to accommodate clusters of shear connectors welded to steel girders or embedded in concrete girders. In this research, ultra-high performance fibre-reinforced concrete (UHPFRC) and high-modulus glass fibre reinforced polymer bars are utilized in the closure strip between the adjacent precast for enhanced strength and durability. Two actual-size, GFRP-reinforced, precast FDDPs were erected to perform fatigue tests using the foot print of the truck wheel loading specified in the Canadian Highway Bridge Design Code (CHBDC). Each FDDP had 200 mm thickness, 2500 mm width and 3700 mm length in the direction of traffic and rest over braced twin-steel girder system. The transverse closure strip between connected precast FDDPs has a width of 200 mm with female-to-female vertical shear key designated as C-shape joint to increase moment capacity along the interface between the UHPFRC and the precast FDDP along the joint. GFRP bars in the precast FDDPs project into the closure strip with a development length of 175 mm. Two types of fatigue tests were performed, namely: (i) high-cyclic constant amplitude fatigue loading followed by loading the slab monotonically to-collapse; and (ii) low-cyclic accelerated variable amplitude cyclic loading. Overall, the test results demonstrated the excellent fatigue performance of the developed closure strip details. In addition, the ultimate load carrying capacity of the slab was far greater than the factored design wheel load specified in CHBDC.
One of the prefabricated bridge system used to accelerate bridge construction is the precast full... more One of the prefabricated bridge system used to accelerate bridge construction is the precast full-depth deck panel (FDDP) with transverse joint placed over steel or concrete girders. In this system, grouted pockets are provided to accommodate clusters of shear connectors connected to steel or concrete girders. In this research, ultra-high performance fibre-reinforced concrete (UHPFRC) and high-modulus glass fibre reinforced polymer (GFRP) bars are utilized in the closure strip between the adjacent precast FDDPs for enhanced strength and durability. Two actual-size, GFRP-reinforced, precast FDDPs were erected to perform fatigue tests using the foot print of the truck wheel loading specified in the Canadian Highway Bridge Design Code (CHBDC). Each FDDP had 200-mm thickness, 2500-mm width and 3700-mm length in the direction of traffic and rest over braced twin-steel girder system. The transverse closure strip between connected precast FDDPs has a width of 100-mm with zigzag-shape from each side of the joint to increase moment capacity along the interface between the UHPFRC and the precast FDDP along the joint. GFRP bars in the precast FDDPs project into the closure strip with a development length of 175-mm. Two types of fatigue tests were performed, namely: (i) high-cyclic constant amplitude fatigue loading followed by monotonically loading to-collapse; and (ii) low-cyclic accelerated variable amplitude fatigue loading. Overall, the test results demonstrated the excellent fatigue performance of the developed closure strip details. In addition, the ultimate load carrying capacity of the FDDP was far greater than the factored design wheel load specified in CHBDC.
Fiber Reinforced Polymer (FRP) bars are rapidly becoming an experienced alternative to convention... more Fiber Reinforced Polymer (FRP) bars are rapidly becoming an experienced alternative to conventional steel reinforcing bars, especially for severely exposed structures like bridges. Glass Fiber Reinforced Polymer (GFRP) bars not only exclude the durability problem associated with the corrosion of reinforcing steel bars, but also provide remarkably improved capacity due to their high tensile strength compared to that of reinforcing steel bars. First, this paper presents an experimental program on the bond strength of sand-coated GFRP bars embedded in high-performance concrete (HPC) with headed anchorage ends. Pullout tests were conducted on a few concrete blocks to study the effects of varying parameters on their bond characteristics, namely: embedment length, bar diameter and concrete. Second, an analytical investigation was conducted on the development length of the GFRP bars based on the experimental findings. And then, an expression for the development length of headed-end GFRP bars embedded in high-performance concrete was proposed.
There is a growing need for durable and resilient prefabricated bridge systems which facilitate r... more There is a growing need for durable and resilient prefabricated bridge systems which facilitate rapid completion of on-site activities in order to minimize the impact on the travelling public. Prefabricated bridges can provide higher quality, accelerated, and safer construction. However, greater offsite prefabrications of bridge components necessitates an increased reliance on the long-term performance of field-installed connections between these components. Of particular interest here, ultra-high performance concrete (UHPC) can exhibit exceptional bond when cast against previously cast concrete and can
significantly shorten the development length of embedded discrete glass fiber reinforced polymer (GFRP) bars. With the recent innovations in bridge infrastructure replacement, the use of UHPC in closure strips between precast concrete bridge segments became the main focus of bridge owners for its superior strength and durability. To increase competitiveness in supplying UHPC to bridge owners in Canada, this collaborative research with the industry is looking into an innovative UHPC design that combines both
high concrete compressive strength, and enhanced durability and rheology. It is essential to produce
design standards and performance-based specifications of UHPC through experimental trial and errors due to lack of reliable information in this subject in the related standards and literature. This research investigates different UHPC mixes designed to reach the desired strength and rheology. While UHPC materials clearly outperform conventional concrete in mechanical and durability performance, their
production is proprietary and the development of economically competitive alternatives is warranted.
Throughout this research, the desired fresh and hardened concrete properties as well as practical mixing
procedure were achieved and reported herein.
Fiber Reinforced Polymer (FRP) bars are rapidly becoming an experienced alternative to convention... more Fiber Reinforced Polymer (FRP) bars are rapidly becoming an experienced alternative to conventional steel reinforcing bars, especially for severely exposed structures like bridges. Glass Fiber Reinforced Polymer (GFRP) bars not only exclude the durability problem associated with the corrosion of reinforcing steel bars, but also provide remarkably improved capacity due to their high tensile strength compared to that of reinforcing steel bars. First, this paper presents an experimental program on the bond strength of sand-coated GFRP bars embedded in high-performance concrete (HPC) with headed anchorage ends. Pullout tests were conducted on a few concrete blocks to study the effects of varying parameters on their bond characteristics, namely: embedment length, bar diameter and concrete. Second, an analytical investigation was conducted on the development length of the GFRP bars based on the experimental findings. And then, an expression for the development length of headed-end GFRP bars embedded in high-performance concrete was proposed.
The 2014 PCI Convention and National Bridge Conference, Sep 2014
Corrosion of reinforcing steel in bridge decks decreases life expectancy of bridge superstructure... more Corrosion of reinforcing steel in bridge decks decreases life expectancy of bridge superstructure, leading to costly and frequent maintenance or replacement. The use of glass fiber reinforced polymer (GFRP) bars as internal reinforcement is a viable option for the replacement of deteriorated concrete bridge deck slabs due to steel bar corrosion. The proposed research investigates the use of ribbed-surface GFRP bars in cast-in-place bridge deck slabs as well as precast bridge deck slab of prefabricated full-depth deck panels to accelerate bridge construction. In this research, three joints between precast panels were developed using straight GFRP bars embedded in a closure strip filled with ultra-high performance fiber reinforced concrete (UHPFRC). High-performance concrete of 70-MPa compressive strength was used to cast the prefabricated panels. Two control cast-in-place slabs reinforced with steel bars and GFRP bars, respectively, were casted to form the baseline of the structural performance of the developed jointed panels. Concentric and eccentric wheel loading were applied at the joint to expose it to pure bending and combined bending and shear, respectively. Results show that precast slab with zigzag-shaped closure strip is as good as the steel-reinforced and GFRP-reinforced cast-in-place slabs with respect to ultimate flexural strength. The jointed slab with eccentric loading showed slight increase in ultimate load that that with concentric loading, while the mode of failure changed from flexural to combined flexural and shear.
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Papers by Mahmoud SAYED AHMED
significantly shorten the development length of embedded discrete glass fiber reinforced polymer (GFRP) bars. With the recent innovations in bridge infrastructure replacement, the use of UHPC in closure strips between precast concrete bridge segments became the main focus of bridge owners for its superior strength and durability. To increase competitiveness in supplying UHPC to bridge owners in Canada, this collaborative research with the industry is looking into an innovative UHPC design that combines both
high concrete compressive strength, and enhanced durability and rheology. It is essential to produce
design standards and performance-based specifications of UHPC through experimental trial and errors due to lack of reliable information in this subject in the related standards and literature. This research investigates different UHPC mixes designed to reach the desired strength and rheology. While UHPC materials clearly outperform conventional concrete in mechanical and durability performance, their
production is proprietary and the development of economically competitive alternatives is warranted.
Throughout this research, the desired fresh and hardened concrete properties as well as practical mixing
procedure were achieved and reported herein.
significantly shorten the development length of embedded discrete glass fiber reinforced polymer (GFRP) bars. With the recent innovations in bridge infrastructure replacement, the use of UHPC in closure strips between precast concrete bridge segments became the main focus of bridge owners for its superior strength and durability. To increase competitiveness in supplying UHPC to bridge owners in Canada, this collaborative research with the industry is looking into an innovative UHPC design that combines both
high concrete compressive strength, and enhanced durability and rheology. It is essential to produce
design standards and performance-based specifications of UHPC through experimental trial and errors due to lack of reliable information in this subject in the related standards and literature. This research investigates different UHPC mixes designed to reach the desired strength and rheology. While UHPC materials clearly outperform conventional concrete in mechanical and durability performance, their
production is proprietary and the development of economically competitive alternatives is warranted.
Throughout this research, the desired fresh and hardened concrete properties as well as practical mixing
procedure were achieved and reported herein.
due to mean wind force, quasi-static caused by low frequency wind force fluctuation and resonant component caused by low wind force fluctuation near the structure’s first mode natural frequency (Tamura, 2003). This assignment presents the wind static loads and predicts the relative force and moment per floor according ASCE 7-02 for 42 story building.
Two basic technologies are used for WMA; Foaming (introducing water in WMA) and additives (organic, and chemical). Each process through performance graded system (PG), and job mix formula (JMF) has impact on bitumen production with respect to viscosity, temperature, rutting, resilient modulus, moisture & indirect tensile strength (ITR) and its performance.