2013 Session: 290

• Laboratory Investigation of Self-Consolidating Concrete Containing Sustainable Technologies: Recycled Asphalt Pavements, Fly Ash, & Slag
  Abstract: The use of sustainable technologies such as supplementary cementitious materials (SCMs), and/or recycled materials is expected to adversely affect the performance of concrete mixtures. However, it is imperative to qualify and implement such mixtures in practice, if the required specifications of their intended application are met. This paper presents the results of a laboratory investigation of self-consolidating concrete (SCC) contacting sustainable technologies. Twelve mixes were prepared with different combinations of fly ash, slag, and Recycled Asphalt Pavement (RAP). Fresh and hardened concrete properties were measured, as expected the inclusion of the sustainable technologies affected both fresh and hardened concrete properties. Analysis of the experimental data indicated that inclusion of RAP not only reduces the ultimate strength, but it also affected the compressive strength development rate. The addition of RAP to mixes showed a consistent effect, with a drop in strength after 3, 14, and 28 days as the RAP content increased from 0 to 50%. However, most of the mixes satisfied SCC fresh properties requirements, including mixes with up to 50% RAP. Moreover, several mixes satisfied compressive strength requirement for pavements and bridges, those mixes included relatively high percentages of SCMs and RAP.  
  Authors: Mahmoud, Enad; Ibrahim, Ahmed; El-Chabib, Hassan; Patibandla, Varun
  Authors: Mahmoud, Enad; Ibrahim, Ahmed; El-Chabib, Hassan; Patibandla, Varun
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-1959
• Comparison of the Superpave Gyratory and Proctor Compaction Methods for the Design of Roller-Compacted Concrete Pavements
  Abstract: Roller-compacted concrete (RCC) is gaining popularity as a paving alternative for a number of roadway applications. RCC is a zero-slump concrete mixture that does not require forms, reinforcing, jointing or finishing. This type of material combines the advantages of conventional concrete pavements with the ease of construction of an asphalt pavement, and can be opened to traffic more quickly than conventional concrete pavements. The Superpave Gyratory Compactor was investigated as an alternative to Proctor compaction (ASTM D1557) for the design of RCC paving mixtures. Seventeen mix designs were generated, encompassing a range of aggregate sources, gradation types, and natural sand contents. In general, the Gyratory method did not produce equivalent designs to the Proctor method, such that the Gyratory method resulted in higher densities and lower optimum moisture contents. Also, gyratory compaction tended to generate a maximum, or ‘terminal’ achievable moisture content, regardless of the amount of moisture mixed in the specimen, and the corresponding densities continued to increase, rather than displaying the parabolic relationship typical of proctor compaction. The highest densities by both compaction methods tended to be achieved for blend gradations that most closely followed the maximum density line and included the greatest percentages of natural sand.
  Authors: Williams, Stacy Goad
  Authors: Williams, Stacy Goad
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-2110
• PROPERTIES OF PREPLACED AGGREGATE CONCRETE CAST IN AIR AND UNDER WATER
  Abstract: Producing good quality concrete requires proper placement and compaction during manufacturing. Among these known placement methods are in-air and preplaced aggregate concrete (PAC). PAC is a method in which coarse aggregate is first placed and compacted in the formworks and then cement mortar/grout is injected to fill the voids in between the coarse aggregates. However, there remains a need for a better understanding of the properties of such concrete when cast both in-air and underwater. Concrete mixtures were prepared at two w/c ratio of 0.35 and 0.45 and with two different coarse aggregates gradations. Specimens were prepared in air as well as at one meter depth underwater using gravity conventional method and preplaced aggregate method. Unit weight, air content and flow table tests were conducted for fresh concrete. Compressive strength (7 and 28-day), flexural strength, ultrasonic pulse velocity and shrinkage cracking tests were performed on the hardened concrete. Concrete slices were removed to assess the presence and distribution of coarse aggregates in concrete. The results reveal that PAC yields similar fresh concrete properties to the conventional concrete. PAC had higher compressive and flexural strength in particular with the w/c 0.45 mixtures. The PAC had better quality when pouring underwater as compared to free-fall concrete into water. These results were supported by visual examination as well as ultrasonic pulse velocity testing. Cracking was significantly less for all PAC concrete mixtures under investigation. Further studies, pilot investigations need to be performed to validate the findings of this work. Applicators should consider PAC as an alternative method in underwater concrete works.
  Authors: Abou-Zeid, Mohamed Nagib; Metawie, Ibrahim; El Deeb, Ahmed; Hosny, Amir; Khalifa, Mostafa; Youssef, Sameh; Assad, Minass
  Authors: Abou-Zeid, Mohamed Nagib; Metawie, Ibrahim; El Deeb, Ahmed; Hosny, Amir; Khalifa, Mostafa; Youssef, Sameh; Assad, Minass
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-1838
• Working Time, Setting Behavior, and Maturity of Concrete Mixtures and their Relationships
  Abstract: Concrete has to be workable for a certain time of period for quality construction, from placing to finishing. The working time limit, as defined by Iowa DOT, is the elapsed time from the time when cementitious materials of a concrete mixture are mixed with water to the time when the concrete has a penetration resistance of 200 psi. In the present study, working time limits of pavement concrete mixtures made with two selected retarders, with and without fly ash replacement, were measured under three different temperatures (65, 75, and 85F), and the results are compared with those measured in 1980s. A new approach to predicting concrete penetration resistance is developed based on the concrete maturity, or time-temperature factor (TTF). The results indicate that probably due to the changes in modern concrete materials (such as cement and admixture properties), some newly measured working time limits are up to 22% higher than those measured in 1980s. Concrete penetration resistance correlates well with the concrete maturity, or TTF. This relationship enables engineers to assess penetration resistance of field concrete any time, with no special consideration for the concrete curing condition.
  Authors: Hou, Qizhe; Ouyang, Chengsheng; Wang, Kejin
  Authors: Hou, Qizhe; Ouyang, Chengsheng; Wang, Kejin
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-2290
• Forensic Investigation of Uncontrolled Concrete Bridge Parapet Cracking
  Abstract: The Ohio Department of Transportation has recently identified the problem of wide-spread premature cracking of concrete bridge parapets throughout its District 12 region (Northeast Ohio). Many of the bridge decks that contain these prematurely cracked parapets are of relatively recent construction. In severe cases, replacement of the parapet may be required before replacement of the bridge deck itself. This incurs a sunk cost upon the bridge owner, as the parapets will again be replaced during the regularly scheduled replacement of the bridge deck. In a recent instance, the replacement of a cracked parapet (without replacing the deck) cost District 12 approximately $140,000. In addition, parapet walls are a crucial safety feature of roadway bridge construction, and severe deterioration of these barriers could introduce a significant safety hazard. Premature cracking of concrete bridge parapets is a potentially complex problem, with a plethora of possible causes. The objective of this study was to determine the reasons for uncontrolled concrete bridge parapet cracking, and to provide recommendations to ODOT to prevent such cracking in the future. Potential factors examined in this study included: properties of the concrete mixtures used, construction methods, joint details, composite structural action, and durability of the concrete and reinforcement, among others. Identifying the cause of, and avoiding this problem in the future, has several benefits, including: a potential cost savings for the district, increasing the safety of these structures in future construction, and increasing the overall understanding of the durability of these structures.
  Authors: Bazzo, Jeffrey; Delatte, Norbert Joseph; Kalabon, Amy
  Authors: Bazzo, Jeffrey; Delatte, Norbert Joseph; Kalabon, Amy
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-2834
• Strength at Early Age and Shrinkage Behavior of High Performance Concrete
  Abstract: In recent decades, High Performance Concrete (HPC) has been used in bridge decks due to its enhanced strength and durability compared to traditional concrete. However, during deck replacement project where the traffic is controlled by full or partially lane closure, it has been shown that truck loads cause cracking in HPC at early age. There is a need for an early age HPC with high strength to help mitigate the cracks while maintaining shrinkage properties.The objective of this paper is to investigate the effect of accelerator and shrinkage reducing admixture on the early age (e.g., 8-24 hours) strength as well as the drying free shrinkage of HPC including slag as a replacement. This work was performed as a part of an overall study for the New Jersey Turnpike Authority (NJTA) to develop technical specifications for high early strength-high performance concrete (HES-HPC) applied to concrete decks during staged construction. In this study, six different slag mixes including set-accelerating admixture and shrinkage reducing admixture were tested at early age (e.g., 8 and 12 hrs.) to a later age at 56 days. Results show that higher accelerator dosages with 14-day wet-curing conditions increase the early age strength, without adverse effects on the drying free shrinkage. Additionally, higher accelerator dosages in conjunction with dry-curing conditions caused drying shrinkage strains higher than the specified limits.
  Authors: Na, Chaekuk; Nassif, Hani; Johnsen, W. Scott
  Authors: Na, Chaekuk; Nassif, Hani; Johnsen, W. Scott
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-4986
• Comparison of the Superpave Gyratory and Proctor Compaction Methods for the Design of Roller-Compacted Concrete Pavements
  Authors: Williams, Stacy
  Authors: Williams, Stacy
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 290
  Paper Number: 13-2110
• Strength at Early Age and Shrinkage Behavior of High Performance Concrete
  Authors: Na, Chaekuk
  Authors: Na, Chaekuk
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 290
  Paper Number: 13-4986
• Factors Influencing the Early-age Volume Change of Expansive Cements Relevant for Bridge Deck Concrete
  Abstract:

  Expansive cements were developed to mitigate shrinkage cracking by means of providing early-age expansion. The increase in volume during the hydration of expansive cement plays a crucial role in development of residual compressive stress which can compensate the tensile stresses induced due to drying shrinkage. This paper reports the early-age deformation (restrained and unrestrained) of cement paste and concrete incorporating two different expansive components: calcium sulfoaluminate-based that forms ettringite, and CaO-based that forms calcium hydroxide crystals. A noticeable difference in the rate of expansion of the two different expansive systems is observed. Most of the expansion in CaO-based system occurs within 24 hours compared to several days in calcium sulfoaluminate-based system. The effect of mineral admixtures on early-age deformation of expansive cements is also investigated. The class ‘C’ fly ash appears to have increased the expansion whereas silica fume decreased the extent of expansion. The rate at which material gains strength and develops resistance against the deformation was identified as a potential factor influencing the expansion. Additionally, the importance of set time is discussed in correctly estimating the “effective” expansion.

  Authors: Chaunsali, Piyush
  Authors: Chaunsali, Piyush
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 290
  Paper Number: 13-3748
• Factors Influencing the Early-age Volume Change of Expansive Cements Relevant for Bridge Deck Concrete
  Authors: Chaunsali, Piyush
  Authors: Chaunsali, Piyush
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 290
  Paper Number: 13-3748