Vibration Study for Consolidation of Portland Cement Concrete

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.

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A Review on Fly Ash Based Geopolymer Rubberized Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.700.183 ◽

2016 ◽

Vol 700 ◽

pp. 183-196 ◽

Cited By ~ 2

Author(s):

Ahmad Azrem Azmi ◽

Mohd Mustafa Al Bakri Abdullah ◽

Che Mohd Ruzaidi Ghazali ◽

Andrei Victor Sandu ◽

Kamarudin Hussin ◽

...

Keyword(s):

Portland Cement ◽

Unit Weight ◽

Hardened Concrete ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Freezing And Thawing ◽

Tire Rubber ◽

Air Content ◽

Waste Tire ◽

Waste Tire Rubber

Utilization of waste materials such as waste tire rubber in the building industry can help prevent environmental pollution whilst contributing to the design of more economical buildings. Preliminary studies show that workable rubberized portland cement concrete mixtures can be made provided that appropriate percentages of tire rubber are used in such mixtures. This article provides the overview of some of published paper using tire waste rubber in portland cement concrete. The researchers mostly investigated the properties of fresh and hardened concrete. The workability, density, air content, unit weight, compressive strength, modulus of elasticity, freezing and thawing resistance, abrasion resistance and thermal properties of the waste tire rubber in concrete were discussed.

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Changing the Shape and Location of Pavement Load Transfer Devices

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198105190700111 ◽

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.

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Development of a Capacitor Probe to Detect Subsurface Deterioration in Concrete

MRS Proceedings ◽

10.1557/proc-503-231 ◽

1997 ◽

Vol 503 ◽

Cited By ~ 2

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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