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Full-Text Articles in Engineering
Epoxy Interlocking: A Novel Approach To Enhance Frp-To-Concrete Bond Behavior, Cheng Jiang, Baolin Wan, Yu-Fei Wu, John Omboko
Epoxy Interlocking: A Novel Approach To Enhance Frp-To-Concrete Bond Behavior, Cheng Jiang, Baolin Wan, Yu-Fei Wu, John Omboko
Civil and Environmental Engineering Faculty Research and Publications
This paper presents a novel approach which can enhance the interfacial bond behavior between fiber reinforced polymer (FRP) composite material and concrete. Epoxy ribs are formed by grooving on the concrete surface before epoxy is applied. The dowel action from the epoxy ribs leads to an “epoxy interlocking” effect. The mechanism of the proposed epoxy interlocking approach was analyzed in this paper from both adhesion and interlocking aspects. Furthermore, the partial interaction of the epoxy interlocking was quantified and calibrated by experimental results. The epoxy interlocking in the tested specimens led to an 88.8% increase in bond strength on average. …
Enhancing Frp-To-Concrete Bond Behavior By Epoxy Ribs, Cheng Jiang, Baolin Wan, John Omboko
Enhancing Frp-To-Concrete Bond Behavior By Epoxy Ribs, Cheng Jiang, Baolin Wan, John Omboko
Civil and Environmental Engineering Faculty Research and Publications
The bond between external bonding (EB) of fiber reinforced polymer (FRP) composite materials to concrete is the weakest link in the strengthened concrete flexural members. There are three mechanisms to transfer the interfacial shear between FRP and the concrete substrate, i.e., adhesion, interlocking and friction. This paper proposes a new approach by grooving on the concrete surface before applying epoxy to make epoxy ribs to increase interlocking. An experimental program was conducted to verify the effectiveness of the proposed epoxy ribs. Six grooves perpendicular to the fiber direction were cut on the bonding surface of the concrete blocks. The grooves …
The Role Of Shrinkage Strains Causing Early-Age Cracking In Cast-In-Place Concrete Bridge Decks, Tayyebeh Mohammadi, Baolin Wan, Christopher M. Foley
The Role Of Shrinkage Strains Causing Early-Age Cracking In Cast-In-Place Concrete Bridge Decks, Tayyebeh Mohammadi, Baolin Wan, Christopher M. Foley
Civil and Environmental Engineering Faculty Research and Publications
Early-age cracking in cast-in-place reinforced concrete bridge decks is occurring more frequently now than three decades ago and principle factors that lead to early-age deck cracking are not fully understood. A finite element (FE) simulation methodology for assessing the role of shrinkage-induced strains in generating early-age bridge deck cracking is described. The simulations conducted indicate that drying shrinkage appears to be capable of causing transverse (and possibly longitudinal) bridge deck cracks as early as 9 to II days after bridge deck placement. The drying-shrinkage induced stresses would result in transverse cracking over interior pier supports in a typical bridge superstructure …
Evaluation Of Bridge Maintenance Interventions Under Changing Deterioration Rates: A Markovian-Based Methodology, Dilum Fernando, Baolin Wan, Scott Walbridge
Evaluation Of Bridge Maintenance Interventions Under Changing Deterioration Rates: A Markovian-Based Methodology, Dilum Fernando, Baolin Wan, Scott Walbridge
Civil and Environmental Engineering Faculty Research and Publications
Markovian transition probability matrices employing condition states are often used in bridge management systems to determine optimal intervention strategies. This approach assumes a constant deterioration matrix throughout the entire analysis period. However, in order to adequately model and evaluate intervention options such as fiber-reinforced polymer (FRP) strengthening, it is necessary to model the impact of the intervention on the deterioration rate. This paper presents a Markovian based approach to model interventions that impact deteriorating rates. A model employing this approach is proposed. A methodology to determine the optimal intervention strategy based on steady state probabilities is then presented. The proposed …
Modeling Of Cfrp-Concrete Interface Subjected To Coupled Pull-Out And Push-Off Actions, Tayyebeh Mohammadi, Baolin Wan, Jian-Guo Dai
Modeling Of Cfrp-Concrete Interface Subjected To Coupled Pull-Out And Push-Off Actions, Tayyebeh Mohammadi, Baolin Wan, Jian-Guo Dai
Civil and Environmental Engineering Faculty Research and Publications
This paper presents a finite element (FE) modeling method for predicting the IC debonding failure when the FRP/concrete interface is subjected to coupled pull-out (shear) and push-off (dowel) actions. Damaged plasticity model was used to simulate the behavior of concrete close to FRP/concrete interface. A thin damage band exposed to mixed-mode loading condition was modeled separately along the FRP-concrete interface. Cohesive elements were used to model the FRP/concrete interface. A sensitivity analysis was performed to find the appropriate damaged band dimensions, bending stiffness of FRP, and tensile strength of concrete for the model. The numerical results were validated by the …
Influence Of Mortar Rheology On Aggregate Settlement, Michael F. Petrou, Baolin Wan, Francis Gadala-Maria, Venkata Giri Kolli, Kent A. Harries
Influence Of Mortar Rheology On Aggregate Settlement, Michael F. Petrou, Baolin Wan, Francis Gadala-Maria, Venkata Giri Kolli, Kent A. Harries
Civil and Environmental Engineering Faculty Research and Publications
The influence of the rheology of fresh concrete on the settlement of aggregate is examined. Fresh concrete exhibits a yield stress that, under certain conditions, prevents the settlement of coarse aggregate, although its density is larger than that of the suspending mortar. Calculations, based on estimates of the yield stress obtained from slump tests, predict that aggregate normally used in concrete should not sink. To test this prediction, the settlement of a stone in fresh mortar is monitored. The stone does not sink in the undisturbed mortar (which has a high yield stress), but sinks when the mortar is vibrated, …