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Full-Text Articles in Engineering

A Simple, Robust, And On-Site Microwave Technique For Determining Water-To-Cement Ratio (W/C) Of Fresh Portland Cement-Based Materials, K. Mubarak, Karl Joseph Bois, R. Zoughi Oct 2001

A Simple, Robust, And On-Site Microwave Technique For Determining Water-To-Cement Ratio (W/C) Of Fresh Portland Cement-Based Materials, K. Mubarak, Karl Joseph Bois, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Inspection and evaluation of cement-based materials such as concrete is of great interest to the construction industry. In particular, real-time and on-site evaluation of water-to-cement ratio (w/c) is an important practical issue, since the compressive strength of a concrete structure is significantly influenced by its w/c. Currently, there is no single real-time, on-site, relatively in-expensive, easy-to-implement, and operator friendly technique for evaluating this parameter. Microwave nondestructive testing and evaluation techniques have shown great promise when used for inspection and evaluation of the properties of cement-based materials. In this paper, the optimal design of a monopole antenna probe used to evaluate …


Near-Field Microwave Non-Invasive Determination Of Nacl In Mortar, Karl Joseph Bois, Aaron D. Benally, R. Zoughi Jul 2001

Near-Field Microwave Non-Invasive Determination Of Nacl In Mortar, Karl Joseph Bois, Aaron D. Benally, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

In recent years near-field microwave nondestructive testing and evaluation techniques have shown great promise for evaluating different properties of cement-based structures. An important issue regarding the inspection of these structures is the ability to determine the presence and evaluate the content of chloride in them. Chlorides can be introduced in these structures in many different ways including when salts are present in their mixing water. Consequently, for this investigation, two sets of 8" × 8" × 8" (203mm) cubic mortar specimens were prepared each with a water-to-cement (w/c) ratio of 0.5 and 0.6, respectively, and both sets with sand-to-cement ratios …


Measurement And Monitoring Of Microwave Reflection And Transmission Properties Of Cement-Based Specimens, Sergey Kharkovsky, M. F. Akay, U. C. Hasar, C. D. Atis Jan 2001

Measurement And Monitoring Of Microwave Reflection And Transmission Properties Of Cement-Based Specimens, Sergey Kharkovsky, M. F. Akay, U. C. Hasar, C. D. Atis

Electrical and Computer Engineering Faculty Research & Creative Works

The results of measurement and monitoring of reflection and transmission properties of cement-based specimens (blocks of mortar, concrete) during long time of their service lives, including hydration process, and different curing conditions at microwave frequencies (X-band) are presented. A simple and inexpensive measurement system that utilizes the nondestructive and contactless free space method is used. Dependencies of the reflection and transmission coefficients on water-to-cement ratio, preparing and curing conditions of the specimens are demonstrated. It is shown that the reflection coefficient is approximately stable after hydration process while the transmission coefficient changes during long time of the specimen''s service life. …


Development And Evaluation Of Cement-Based Materials For Repair Of Corrosion-Damaged Reinforced Concrete Slabs, Rongtang Liu, J. Olek Jan 2001

Development And Evaluation Of Cement-Based Materials For Repair Of Corrosion-Damaged Reinforced Concrete Slabs, Rongtang Liu, J. Olek

JTRP Technical Reports

In this study, the results of an extensive laboratory investigation conducted to evaluate the properties of concrete mixes used as patching materials to repair reinforced concrete slabs damaged by corrosion are reported. Seven special concrete mixes containing various combinations of chemical or mineral admixtures were developed and used as a patching material to improve the durability of the repaired slabs. Physical and mechanical properties of these mixes, such as compressive strength, static modulus of elasticity, dynamic modulus of elasticity, and shrinkage were evaluated. Durability-related parameters investigated included resistance of concrete to penetration of chloride ions and freeze-thaw resistance. The results …