Concrete evaluation

Since the permeability significantly influences the deterioration of concrete, evaluation of water permeability in cracked HPFRCC seans a key factor to describe the durability performance of given materials. Superior impermeability of HPFRCC has been observed by several researchers. Lepech and Li (2005) studied the water permeability of cracked HPFRCC and reinforced mortar specimens. When subjected to identical tensile deformation, the HPFRCC and reinforced mortar specimens exhibited very different cracking patterns and widths. They found that the cracked HPFRCC exhibits nearly the same permeability as sonnd concrete, even when strained in tension to several percent (Figure 6.8). Homma et al. (2009) also evaluated the water permeability of cracked... 

The mechanical properties of concrete evaluated were the compressive and tensile strengths, at 7 and 28 days. Each result represents an average of 3 specimens. The compressive strength tests where performed according to the NP EN 12390-3 [16], where as the tensile strength test adopted was the Brazilian method, according to NBR 7222 [17], which determines the tensile strength by diametrical compression of specimens. 

Quantitative and Rapid Measurement of the Air-Void System in Fresh Concrete. Evaluates a new method for determining air void characteristics in fresh concrete. The method uses a laser counting device to evaluate the number and distribution of air voids. The measurements are made on a core extracted from a sample of fresh concrete frozen with liquid nitrogen. 30 pages. SHRP-ID/UFR-91-519... 

E.4.4 Place leaves, sticks, and/or grass in plastic bags made from polyethylene, starch Biobag, and BioTuf ecoflex. Add one quart of water and place the bags outside on the concrete. Evaluate the amount of water leaking from the bags after 1 hour, 4 hours, 8 hours, 1 day, and 7 days. What can be the causes of the leakage. 

Use EPRI data (EPRI NP-5228, Seismic Verification of Nuclear Plant Equipment Anchorage, Volume 1, Development of Anchorage Guidelines, May 1987) converted to the 2500 psi concrete for cast-in-place and grouted-in-place bolts, expansion, lead shield and lead cinched anchors. Use safety factors of 3 and 4 for non-shell and shell expansion anchors, respectively. Use 1973 AISC Code (Manual of Steel Construction, 7th Edition) requirements for steel connecting members and bolts. Use ACI Standard 349-85 (Code Requirements for Nuclear Safety Related Concrete Structures, 1985) for concrete evaluation. 

We have presented a neural network based spectrum classifier (NSC) aimed at ultrasonic resonance spectroscopy. The ultrasonic spectroscopy and the NSC has been evaluated in many industrial applications, such as concrete inspection, testing of aerospace composite structures, ball bearings, and aircraft multi-layer structures. The latter application has been presented in some detail. 

Nesvijski, E.G., Nesvijski, T.E. Kaiser and Felicity Effects and Their Application for Evaluation of Concrete by Acoustic Emission. ASNT s Fall Conference, Seattle, WA, 1996. 

Nesvijski, E.G., Nogin, S.I. Acoustic Emission Technics for Nondestructive Evaluation of Stress of Concrete and Reinforced Concrete Structures and Materials. Third Conference on Nondestructive Evaluation of Civil Structures and Materials, Boulder, CO, 1996. Nesvijski, E. G. Failure Forecast and the Acoustic Emission Silence Effect in Concrete. ASNT s Spring Conference, Houston, TX, 1997. 

Prestressed (posttensioned) concrete tanks cost about 20 percent more than steel tanks of the same capacity. Once installed, however, concrete tanks require veiy little maintenance. A true comparison with steel would, therefore, require evaluating the maintenance cost of both types. 

D. Whiting u. D. Stark, Cathodic Protection for Reinforced Concrete Bridge Decks B Field Evaluation, Final Report, Construction Technology Laboratories, Portland Cement Association, Skokie, Illinois, NCHRP 12-13A (1981). 

In addition to these types of evaluations, the incident reporting and near miss systems should be monitored for improvements in performance that can be attributed to the program. On the basis of feedback from these and other sources such as changes in quality levels or efficiency, modifications should be made to the program to enhance and sustain its effectiveness. Concrete evidence regarding the benefits arising from the program should be communicated to those involved. 

Mounting configuration and operating envelope Industrial standards, such as the rathbone severity chart, assume that the machine is rigidly mounted on a suitable concrete foundation. Machines mounted on deck-plate or on flexible foundations have higher normal vibration profiles and cannot be evaluated using these standards. 

Brown and Fessler have conducted a laboratory evaluation of conductive mastics that can be brushed or sprayed onto the concrete surface to achieve the necessary thickness. However, the most extensive study on conductive paints for cathodic protection purposes has been undertaken by the Federal Highway AuthorityA total of nine commercially available resins were evaluated in this work. It was shown that neither thermal cycling, freeze thawing nor the application of cathodic protection currents... 

Figure 26.42 compares the correlation coefficient between a road test on wet concrete and the laboratory side force measurements of the six compounds of Table 26.2 on blunt, wet Alumina 180 (a) with a log oxv-log v evaluation and (b) with a temperature-log v evaluation. It appears that the... 

Concrete, cement block, and wallboard are the most common w all materials found in laboratories. All can be painted after treatment with an approprite sealer or filler. The choice of paint is very important. Both durability and ease of cleaning must be carefully evaluated. Bargain paints are rarely a bargain in the long run, particularly when labor is such a large part of the cost. 

Hondras, G. (1959). The evaluation of Poisson s ratio and the modulus of materials of a low tensile resistance by the Brazilian (indirect tensile) test with particular reference to concrete. Australian Journal of Applied Science, 10, 245-68. 

Some concrete conclusions on market evaluation for micro reactors are given by the PAMIR study, described above (see Section 1.8.1.2). In this context, it is worth reviewing general essays on the market evaluation of microsystems technology, since in a broader view they follow the same analysis and come to the same conclusions. 

Asphalt concrete is properly proportioned to resist the potentially damaging effects in the road. Asphalt concrete paving mixtures should be evaluated for the following properties stability, flow, air voids, stripping resistance, resilient modulus, compacted density, and unit weight. Table 4.18 provides a list of standard laboratory tests that are presently used to evaluate the mix design or expected performance of fresh and hardened asphalt concrete. 

Today, analytical chemistry has such a wide variety of methods and techniques at its disposal that the search for general fundamentals seems to be very difficult. But independent from the concrete chemical, physical and technical basis on which analytical methods work, all the methods do have one principle in common, namely the extraction of information from samples by the generation, processing, calibration, and evaluation of signals according to the logical steps of the analytical process. 

Analytical chemistry is a problem-solving science. Independent from the concrete analytical method, the course of action, called analytical process, is always very similar. The analytical process starts with the analytical question on the subject of investigation and forms a closed chain to the answer to the problem. Using a proper sampling technique a test sample is taken that is adequately prepared and then measured. The measured data are evaluated on the basis of a correct calibration and then interpreted with regard to the object under study. 

Construct validation suggests that classification is central to and inseparable from theory. Classification of a disorder forms a representation of the theoretical construct that is needed for the basis of elaboration and testing of the theory. A classification system like the DSM provides a means of translating or operationalizing abstract theoretical ideas into more concrete (often behavioral) definitions. Testing the theory (classification system) rests on tests of its internal and external validity. These tests inform us about the adequacy of both the classification system and the theory. It is conceivabe that theory and classification evolve together over time. Theory creates an initial classification scheme that is evaluated and, when refined, informs us about theory. 

The results of this evaluation lead to the conclusion that a rectangular-based cubicle is the preferred room configuration. Additional parameter studies concluded that in the rectangular cubicle configuration, reinforced concrete is the preferred construction material over structural steel. Design of reinforced... 

Arthur, F.H. and Dowdy, A.K. 2003. Impact of high temperatures on efficacy of cyfluthrin and hydroprene applied to concrete to control Tribolium castaneum (Herbst). J. Stored Prod. Res. 39,193-204. Arthur, F.H. and Gillenwater, H.B. 1990. Evaluation of esfenvalerate aerosol for control of stored product insect pests. J. Entomol. Sci. 25, 261-267. 

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