Journal of Materials in Civil Engineering, Oct 1, 2020
AbstractA number of parameters can influence the fluidity of an ultrahigh-performance concrete (U... more AbstractA number of parameters can influence the fluidity of an ultrahigh-performance concrete (UHPC) mix and, hence, its viability for use in construction. These parameters include the carbon cont...
2018Final report, 4/1/2017 - 12/31/2018Steve KahlPDFTech ReportRC-1670Contract 2016-0068BridgesCo... more 2018Final report, 4/1/2017 - 12/31/2018Steve KahlPDFTech ReportRC-1670Contract 2016-0068BridgesConstructionDurabilityMixingProductionStrength of materialsUltra high performance concretenon-proprietarystrengthfield pourbridgefreeze-thawMichiganUnited StatesMichigan. Dept. of Transportation. Research AdministrationEl-Tawil, SherifTai, Yuh-ShiouMeng, BoHansen, WillLiu, ZhichaoRegents of the University of Michigan, Ann ArborMichigan. Dept. of Transportation. Research AdministrationUS Transportation CollectionThe vast majority of field usage of UHPC in the US, to date, has employed pre-packaged, proprietary materials. A previous project funded by MDOT developed a generic, cost-optimized UHPC mix (named MI-UHPC) that performed exceptionally well in the lab but was not well-suited for field implementation. This project explored the reasons why the generic UHPC mix did not scale up. Successful field mixing was achieved by optimizing the mix proportions and changing the mixing procedure. In addition and in order to achieve truly generic UHPC technology, this project also proposed a family of mixes with components sourced from a variety of local suppliers. One of these mixes was used in the Kilgore Road Bridge Restoration Project on the Pine River in Kenockee, Michigan and is one of the earliest field applications of a non-proprietary blend of UHPC in the US. Extensive material testing was conducted to explore the influence of a number of variables on the short and long term properties of the proposed UHPC mix.92
Materials related distress (MRD) characterized by “starburst” type corner spalling at the longitu... more Materials related distress (MRD) characterized by “starburst” type corner spalling at the longitudinal centerline joint, and occasional transverse joint spalling have developed at a rapid rate in a number of jointed plain concrete pavement (JPCP) projects constructed since 1999. The main objective for this project was to isolate the major cause(s) for suspected freeze-thaw deterioration, and to provide recommendations for improved materials specifications in order to ensure long-term freeze-thaw resistance to severe surface exposure conditions (i.e. surface contact with either water or 3% sodium chloride (NaCl)) during repeated freezing and thawing. Four younger ( 5.5%) while the concretes with low air had severe deterioration. A substantial improvement in deicer scaling resistance was obtained for Michigan Department of Transportation's (MDOT’s) low-cement concrete containing slag cement (328 lbs Type I, and 162 lbs slag cement). The improvement was attributed to a better quali...
. The original paper intended to pro-vide a general methodology for modeling early-age tensile cr... more . The original paper intended to pro-vide a general methodology for modeling early-age tensile creepunder the restrained condition based on an existing solid model(B3 model) instead of just giving specific values obtained simplythrough curve fitting to the experimental measurements. Moreover,from the authors’ restrained test, the tensile creep prediction usingB3 model deviates from the measurements at later ages, which areclosely related to q
This paper describes the findings of a recently completed investigation by the University of Mich... more This paper describes the findings of a recently completed investigation by the University of Michigan to identify the causes for premature, mid-slab cracking of joined plain concrete pavement (JPCP) in Michigan. The study found several factors are working interactively to induce slab cracking. The major factor is the support characteristics of the unbound open-graded aggregate base. Deflection testing showed a permanent loss of slab contact with the base (void) exists near the doweled joint. Time history analysis of the deflection data showed that the dowels are very likely loose. Loss of slab-base contact without pumping suggests that post-compaction under heavy vehicle loading or particle degradation is occurring. In addition, the study found that the load transfer efficiency (LTE) across joints has declined since construction. Finite element analysis (ABAQUS) was used to evaluate the extent and significance of these factors on tensile stress and fatigue cracking. Fatigue failure culminates from excessive tensile stress at mid-slab at the slab's topside outer edge. The slab stress predictions correlate well with the deflection-based fatigue model by Wu et al. (1993) suggesting that a threshold corner deflection criteria may be used to determine when loss of slab support is critical.
AbstractSalt scaling is a commonly observed durability issue in concrete exposed to a combined sa... more AbstractSalt scaling is a commonly observed durability issue in concrete exposed to a combined salt and frost attack. This damage is restricted to a very thin surface region causing the removal of ...
In this paper, a two-dimensional geometric model is developed to characterise the air-void system... more In this paper, a two-dimensional geometric model is developed to characterise the air-void system in hardened cement paste. This model consists of non-overlapping circular voids of different size classes randomly placed in the cementitious matrix of a specific size. The major output of this model is the distance of a specific void from its nearest neighbour (void–void spacing). The cumulative distribution function of the nearest void–void spacing fits well the Rosin–Rammler model, from which the probability distribution function is derived. The number and distribution of the voids is obtained from the chord length measurement based on the linear-traverse method. The effect of paste content and air-void saturation on the void spacing is investigated to illustrate gradual increase in void spacing with a higher paste content or the partial filling of air voids. This model is validated by the good correlation between the calculated spacing factor and the tensile strain capacity of concr...
Journal of Materials in Civil Engineering, Oct 1, 2020
AbstractA number of parameters can influence the fluidity of an ultrahigh-performance concrete (U... more AbstractA number of parameters can influence the fluidity of an ultrahigh-performance concrete (UHPC) mix and, hence, its viability for use in construction. These parameters include the carbon cont...
2018Final report, 4/1/2017 - 12/31/2018Steve KahlPDFTech ReportRC-1670Contract 2016-0068BridgesCo... more 2018Final report, 4/1/2017 - 12/31/2018Steve KahlPDFTech ReportRC-1670Contract 2016-0068BridgesConstructionDurabilityMixingProductionStrength of materialsUltra high performance concretenon-proprietarystrengthfield pourbridgefreeze-thawMichiganUnited StatesMichigan. Dept. of Transportation. Research AdministrationEl-Tawil, SherifTai, Yuh-ShiouMeng, BoHansen, WillLiu, ZhichaoRegents of the University of Michigan, Ann ArborMichigan. Dept. of Transportation. Research AdministrationUS Transportation CollectionThe vast majority of field usage of UHPC in the US, to date, has employed pre-packaged, proprietary materials. A previous project funded by MDOT developed a generic, cost-optimized UHPC mix (named MI-UHPC) that performed exceptionally well in the lab but was not well-suited for field implementation. This project explored the reasons why the generic UHPC mix did not scale up. Successful field mixing was achieved by optimizing the mix proportions and changing the mixing procedure. In addition and in order to achieve truly generic UHPC technology, this project also proposed a family of mixes with components sourced from a variety of local suppliers. One of these mixes was used in the Kilgore Road Bridge Restoration Project on the Pine River in Kenockee, Michigan and is one of the earliest field applications of a non-proprietary blend of UHPC in the US. Extensive material testing was conducted to explore the influence of a number of variables on the short and long term properties of the proposed UHPC mix.92
Materials related distress (MRD) characterized by “starburst” type corner spalling at the longitu... more Materials related distress (MRD) characterized by “starburst” type corner spalling at the longitudinal centerline joint, and occasional transverse joint spalling have developed at a rapid rate in a number of jointed plain concrete pavement (JPCP) projects constructed since 1999. The main objective for this project was to isolate the major cause(s) for suspected freeze-thaw deterioration, and to provide recommendations for improved materials specifications in order to ensure long-term freeze-thaw resistance to severe surface exposure conditions (i.e. surface contact with either water or 3% sodium chloride (NaCl)) during repeated freezing and thawing. Four younger ( 5.5%) while the concretes with low air had severe deterioration. A substantial improvement in deicer scaling resistance was obtained for Michigan Department of Transportation's (MDOT’s) low-cement concrete containing slag cement (328 lbs Type I, and 162 lbs slag cement). The improvement was attributed to a better quali...
. The original paper intended to pro-vide a general methodology for modeling early-age tensile cr... more . The original paper intended to pro-vide a general methodology for modeling early-age tensile creepunder the restrained condition based on an existing solid model(B3 model) instead of just giving specific values obtained simplythrough curve fitting to the experimental measurements. Moreover,from the authors’ restrained test, the tensile creep prediction usingB3 model deviates from the measurements at later ages, which areclosely related to q
This paper describes the findings of a recently completed investigation by the University of Mich... more This paper describes the findings of a recently completed investigation by the University of Michigan to identify the causes for premature, mid-slab cracking of joined plain concrete pavement (JPCP) in Michigan. The study found several factors are working interactively to induce slab cracking. The major factor is the support characteristics of the unbound open-graded aggregate base. Deflection testing showed a permanent loss of slab contact with the base (void) exists near the doweled joint. Time history analysis of the deflection data showed that the dowels are very likely loose. Loss of slab-base contact without pumping suggests that post-compaction under heavy vehicle loading or particle degradation is occurring. In addition, the study found that the load transfer efficiency (LTE) across joints has declined since construction. Finite element analysis (ABAQUS) was used to evaluate the extent and significance of these factors on tensile stress and fatigue cracking. Fatigue failure culminates from excessive tensile stress at mid-slab at the slab's topside outer edge. The slab stress predictions correlate well with the deflection-based fatigue model by Wu et al. (1993) suggesting that a threshold corner deflection criteria may be used to determine when loss of slab support is critical.
AbstractSalt scaling is a commonly observed durability issue in concrete exposed to a combined sa... more AbstractSalt scaling is a commonly observed durability issue in concrete exposed to a combined salt and frost attack. This damage is restricted to a very thin surface region causing the removal of ...
In this paper, a two-dimensional geometric model is developed to characterise the air-void system... more In this paper, a two-dimensional geometric model is developed to characterise the air-void system in hardened cement paste. This model consists of non-overlapping circular voids of different size classes randomly placed in the cementitious matrix of a specific size. The major output of this model is the distance of a specific void from its nearest neighbour (void–void spacing). The cumulative distribution function of the nearest void–void spacing fits well the Rosin–Rammler model, from which the probability distribution function is derived. The number and distribution of the voids is obtained from the chord length measurement based on the linear-traverse method. The effect of paste content and air-void saturation on the void spacing is investigated to illustrate gradual increase in void spacing with a higher paste content or the partial filling of air voids. This model is validated by the good correlation between the calculated spacing factor and the tensile strain capacity of concr...
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