Changing the Shape and Location of Pavement Load Transfer Devices

2005 ◽  
Vol 1907 (1) ◽  
pp. 95-101
Author(s):  
James K. Cable
Keyword(s):  
Experimental Design ◽  
Portland Cement ◽  
Load Transfer ◽  
Field Research ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Research Project ◽  
Joint Design ◽  
The Impact ◽  
Initial Results

Load transfer is an important aspect of portland cement concrete joint design. To date, aggregate interlock and round steel dowels have been used to accomplish load transfer. Research was done to examine the use of steel dowels of alternative shapes to provide load transfer. A field research project in Iowa has used two elliptical bars of different sizes at three spacings and numbers of bars per joint. Test sections included bars across the entire joint and sections using bars only in the wheelpaths. The impact of cut, fill, and transition sections was also factored into the experimental design. This paper documents the construction of the project, testing that is being done, and the initial results of the work.

Long-Term Performance of Recycled Portland Cement Concrete Pavement

1996 ◽  
Vol 1525 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Stephen A. Cross ◽  
Mohamed Nagib Abou-Zeid ◽  
John B. Wojakowski ◽  
Glenn A. Fager
Keyword(s):  
Portland Cement ◽  
Test Section ◽  
Load Transfer ◽  
Construction Materials ◽  
Concrete Pavement ◽  
Recycled Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Cement Concrete Pavement ◽  
Portland Cement Concrete Pavement

Over the past years there has been an increasing interest in recycling construction materials, particularly hot-mix asphalt (HMA) and portland cement concrete pavements (PCCP). To this end the Kansas Department of Transportation (KDOT) participated in Demonstration Project 47, Recycling Portland Cement Concrete Pavement, by recycling a moderately D-cracked concrete pavement and monitoring the performance over a 10-year period. The recycled concrete pavement (RCP) aggregate was evaluated in four test sections consisting of two control sections, one test section of portland cement-treated base (CTB) with RCP aggregate, and one test section using RCP aggregate in the PCCP and CTB. An HMA shoulder using RCP as coarse aggregate was also constructed. The test sections were monitored over a 10-year period for performance including faulting, roughness, load transfer, and friction measurements. Faulting, roughness, performance level, and joint distress measurements from KDOT's 1995 pavement condition survey were used to compare the performance of the recycled sections with PCCP of similar age and traffic in the same area of the state. All test sections performed well, with the CTB and PCCP sections with RCP aggregates showing slightly more distress.

Vibration Study for Consolidation of Portland Cement Concrete

1997 ◽  
Vol 1574 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Shane Tymkowicz ◽  
Robert F. Steffes
Keyword(s):  
Portland Cement ◽  
The State ◽  
Department Of Transportation ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Research Project ◽  
Air Content ◽  
Radius Of Influence ◽  
Normal Speed

The Iowa Department of Transportation has discovered an increase in the occurrence of excessively vibrated portland cement concrete (PCC) pavements. The overconsolidation of PCC pavements has been observed in several projects across the state. Overconsolidation is also believed to be a factor in acceleration of premature deterioration of at least two pavement projects in Iowa. To address the problem, a research project in 1995 documented the vibratory practices of PCC slipform paving in Iowa in order to determine the effect of vibration on consolidation and air content of pavement. Paver speed, vibrator frequency, and air content relative to the location of the vibrator were studied. The study concluded that the Iowa Department of Transportation specification of 5,000 to 8,000 vibrations per minute (vpm) for slipform pavers is effective for normal paver speeds on the three projects that were examined. Excessive vibration was clearly identified on one project where a vibrator frequency of 12,000 vpm was discovered. When the paver speed was reduced to half the normal speed, hard air contents indicate that excessive vibration was beginning to occur in the localized area immediately surrounding the vibrator at a frequency of 8,000 vpm. The study also indicates that the radius of influence of the vibrators is smaller than has been claimed.

Quality Control of Portland Cement Concrete Slabs with Wave Propagation Techniques

1996 ◽  
Vol 1544 (1) ◽  
pp. 91-98
Author(s):  
Soheil Nazarian ◽  
Deren Yuan ◽  
Mark R. Baker
Keyword(s):  
Quality Control ◽  
Wave Propagation ◽  
Surface Wave ◽  
Portland Cement ◽  
Body Wave ◽  
Field Testing ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Impact Echo ◽  
The Impact

Coring is normally done to monitor the thickness and quality of portland cement concrete (PCC) slabs during construction. Because this procedure requires a considerable amount of time, it is done at widely spaced intervals. As a result, the most critical points, in terms of strength or thickness, are sometimes not tested. Their repeatability and extreme sensitivity to the properties of surface layer enable wave propagation techniques to be used for quality control. The main advantage of these techniques is that they are nondestructive. Fortunately, these techniques have been automated in the last few years. Two seismic devices (seismic pavement analyzer and a portable version of it called the Lunch Box) have been used extensively for quality control. With them, slabs can be tested at closely spaced points and at a fraction of the cost and time of coring. The main tests used are the impact echo for determining the thickness of the slab, the ultrasonic body wave for determining the modulus, and the ultrasonic surface wave (an offshoot of the spectral analysis of surface waves method) also for determining the modulus. On the basis of extensive field testing on many types of base and subgrade, the techniques in general—and the two devices in particular—are suitable for many quality-control projects. It was found that the most robust method for determining the modulus is the ultrasonic surface wave. The impact echo also works well, as long as enough contrast exists between the properties of the PCC and the underlying materials.

Performance Trends for Portland Cement Concrète General Aviation Pavements in Illinois

1996 ◽  
Vol 1524 (1) ◽  
pp. 194-202 ◽  
Author(s):  
Thomas Van Dam ◽  
James Bildilli
Keyword(s):  
Portland Cement ◽  
Element Model ◽  
General Aviation ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Actual Performance ◽  
Deterioration Rate ◽  
Performance Trends ◽  
And Performance ◽  
The Impact

The deterioration and performance of portland cement concrete general aviation (GA) airport pavements in Illinois are discussed. Two popular design procedures are reviewed, and typical GA pavement sections are structurally evaluated by using the ILLI-SLAB finite-element model. Subjected to GA pavement loading conditions, 125- and 150-mm-thick slabs would be considered structurally adequate, whereas 100-mm-thick slabs would not be expected to perform well. It was determined that slab size, as determined by the ratio of the slab length over the radius of relative stiffness (L/ l) was strongly correlated to pavement distress and performance. As the slab size was increased higher incidences of distress at higher severity levels were observed. Performance trends were identified by using a deterioration rate approach that accounts for the performance of individual sections. It is believed that this procedure reflects actual performance trends by addressing the issues of long-lived pavement sections, the impact of maintenance, and the influence of inspection variability.

scholarly journals Long-term use of modern Portland cement concrete: The impact of Al-tobermorite formation

2021 ◽  
Vol 198 ◽  
pp. 109297
Author(s):  
Ippei Maruyama ◽  
Jiří Rymeš ◽  
Abudushalamu Aili ◽  
Shohei Sawada ◽  
Osamu Kontani ◽  
...  
Keyword(s):  
Portland Cement ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
The Impact

Development of a Capacitor Probe to Detect Subsurface Deterioration in Concrete

1997 ◽  
Vol 503 ◽  
Author(s):  
B. K. Diefenderfer ◽  
I. L. Al-Qadi ◽  
J. J. Yoho ◽  
S. M. Riad ◽  
A. Loulizi
Keyword(s):  
Dielectric Constant ◽  
Portland Cement ◽  
Electromagnetic Waves ◽  
Low Cost ◽  
Complex Dielectric Constant ◽  
Life Cycle Costs ◽  
Parallel Plates ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Set Up

ABSTRACTPortland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. By developing techniques that would enable civil engineers to evaluate PCC structures and detect deterioration at early stages (without causing further damage), optimization of life-cycle costs of the constructed facility and minimization of disturbance to the facility users can be achieved.Nondestructive evaluation (NDE) methods are potentially one of the most useful techniques ever developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part, termed the “loss factor,” describes the conductivity of PCC and the attenuation of electromagnetic waves.Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1 to 40.1MIHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation. A new capacitor probe has been developed which consists of two plates, located within the same horizontal plane, for placement upon the specimen to be tested. Preliminary results show that this technique is feasible and results are promising; further testing and evaluation is currently underway.

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