scholarly journals Anisotropy of reinforced concrete from geophysical methods

2021 ◽  
Vol 53 (3) ◽  
pp. 323-345
Author(s):  
Nevbahar Ekin ◽  
Osman Uyanik
Keyword(s):  
Reinforced Concrete ◽  
Geophysical Methods ◽  
S Wave ◽  
Curing Conditions ◽  
Wave Measurements ◽  
Dependent Change ◽  
Correct Determination ◽  
Uniaxial Compressive Strength Test ◽  
Water Saturated ◽  
Geophysical Measurements

Anisotropy is expressed as the direction-dependent change of material properties and it is a very important parameter to the correct determination of the concrete quality. For the aim of determining the concrete anisotropy, geophysical measurements in the study were carried out on the reinforced concrete samples with different strengths, before concrete strengths were determined from Uniaxial Compressive Strength test. Since the propagation direction of concrete pores and saturation type of it is important parameters in affecting the concrete anisotropy, prepared samples were cured as oven-dried, water-saturated, and dried in outside. Thus, the effects of curing conditions on the anisotropy of reinforced concrete were investigated by geophysical measurements. For this purpose, ultrasonic P and S wave measurements were made on two opposite surfaces of cubic samples with different reinforcement diameters. In addition, a total of 8 resistivity measurements were performed by taking two diagonal measurements on each surface in except of reinforced surfaces of the sample. The velocity and resistivity anisotropies of samples were determined by using the anisotropy relations given in the literature. As a result, it is determined that while reinforcement diameter has no distinctive effect on anisotropy, curing conditions are especially very effective on resistivity anisotropy.

Investigating the Effective Resistivity of Reinforced Concrete Waste Storage Tanks at the Hanford Site

Geophysics ◽  
2021 ◽  
pp. 1-50
Author(s):  
Allan Haas ◽  
Dale F. Rucker ◽  
Marc T. Levitt
Keyword(s):  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Geophysical Methods ◽  
Underground Storage ◽  
Storage Tanks ◽  
Hanford Site ◽  
Underground Storage Tanks ◽  
Effective Resistivity ◽  
Geophysical Surveys ◽  
Wide Range

Industrialized sites pose challenges for conducting electrical resistivity geophysical surveys, as the sites typically contain metallic infrastructure that can mask electrolytic-based soil and groundwater contamination. The Hanford site in eastern Washington State, USA, is an industrialized site with underground storage tanks, piping networks, steel fencing, and other potentially interfering infrastructure that could inhibit the effectiveness of electrical resistivity tomography (ERT) to map historical and monitor current waste releases. The underground storage tanks are the largest contributor by volume to subsurface infrastructure and can be classified as reinforced concrete structures with an internal steel liner. Directly measuring the effective value for the electrical resistivity of the tank, i.e., the combination of individual components that comprise the tank’s shell, is not reasonably possible because they are buried and dangerously radioactive. Therefore, we indirectly assess the general resistivity of the tanks and surrounding infrastructure by developing synthetic ERT models with a parametric forward modeling study using a wide range of resistivity values from 1×10−6 to 1×104 ohm-m, which are equivalent to steel and dry rock, respectively. The synthetic models used the long-electrode ERT method (LE-ERT), whereby steel cased metallic wells surrounding the tanks are used as electrodes. The patterns and values of the synthetic tomographic models were then compared to LE-ERT field data from the AX tank farm at the Hanford site. This indirect method of assessing the effective resistivity revealed that the reinforced concrete tanks are electrically resistive and the accompanying piping infrastructure has little influence on the overall resistivity distribution when using electrically based geophysical methods for characterizing or monitoring waste releases. Our findings are consistent with nondestructive testing literature that also shows reinforced concrete to be generally resistive.

scholarly journals Influence Factors on the Properties of Ultrahigh-Performance Fiber-Reinforced Concrete Cured under the Condition of Room Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Pu Zhang ◽  
Yiliang Huang ◽  
Yongqi Li ◽  
Jun Zhao ◽  
Hengqian Dong ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Fly Ash ◽  
Influence Factors ◽  
Volume Ratio ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Curing Conditions ◽  
Heat Curing ◽  
Composition Materials

Ultrahigh-performance fiber-reinforced concrete (UHPFRC) is a new type of concrete with excellent performance and good application prospects. However, expensive heat curing or high-pressure curing was often adopted to ensure the sufficient compressive strength. This study focuses on improving the compressive strength and workability of UHPFRC by changing the composition materials and the mixture ratios under standard curing conditions. The 0-1 mm and 1∼3 mm sintered bauxite was adopted as coarse aggregate. UHPFRC with high compressive strength and good workability was developed by changing the water-binder ratios, by adding ground-granulated blast furnace slag (GGBFS) or fly ash, and by changing the bauxite content of different particle sizes. When the volume ratio of steel fiber was 3%, the recommend water to binder ratio was 0.194 according to this experiment, the dosage of GGBFS-replaced cement is recommended as 20%, the dosage of fly ash instead of silica fume is recommended as 30%. The recommend ratio of 0-1 mm and 1∼3 mm sintered bauxite was 1.51 : 1. Finally, a kind of UHPFRC material with a compressive strength of 152.4 MPa and a slump of 120 mm was developed under the standard curing conditions.

scholarly journals Petrographic and Mechanical Characteristics of Concrete Produced by Different Type of Recycled Materials

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 264 ◽  
Author(s):  
Petros Petrounias ◽  
Panagiota P. Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Paraskevi Lampropoulou ◽  
Basilios Tsikouras ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Mechanical Characteristics ◽  
Strength Class ◽  
Concrete Strength ◽  
Glass Waste ◽  
Recycled Materials ◽  
Curing Conditions ◽  
Different Types ◽  
Green Glass ◽  
Water Saturated

This paper examined three different types of recycled materials, such as beer green glass, waste tile, and asphalt, which will be used in different mixtures in order to prepare concrete specimens and, more specifically, their effect on concrete strength and how the petrographic characteristics of various recycled materials influenced the durability of C25/30 strength class concrete. Particular emphasis was placed on the effect of artificial microroughness of glassy and smooth surfaces of recycled materials on their final concrete strength. The concrete strength values do not show great variance, but their limited differences have been qualitatively interpreted by a new promising petrographic methodology, including the study of the surface texture of the used aggregate materials. Concretes are produced with constant volume proportions, workability, mixing, and curing conditions while using different sizes of each aggregate type. The aggregates were mixed both in dry and water saturated states in concretes. Concretes that are made by a mixture of beer green glass with quartz primer, as well as of tile with quartz primer, presented the optimum possible results of the compressive strength.

scholarly journals Experimental and Empirical Time to Corrosion of Reinforced Concrete Structures under Different Curing Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmed A. Abouhussien ◽  
Assem A. A. Hassan
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Test ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Cell Potential ◽  
Accelerated Corrosion ◽  
Curing Conditions ◽  
Expected Time ◽  
Corrosion Initiation ◽  
Accelerated Corrosion Test

Reinforced concrete structures, especially those in marine environments, are commonly subjected to high concentrations of chlorides, which eventually leads to corrosion of the embedded reinforcing steel. The total time to corrosion of such structures may be divided into three stages: corrosion initiation, cracking, and damage periods. This paper evaluates, both empirically and experimentally, the expected time to corrosion of reinforced concrete structures. The tested reinforced concrete samples were subjected to ten alternative curing techniques, including hot, cold, and normal temperatures, prior to testing. The corrosion initiation, cracking, and damage periods in this investigation were experimentally monitored by an accelerated corrosion test performed on reinforced concrete samples. Alternatively, the corrosion initiation time for counterpart samples was empirically predicted using Fick’s second law of diffusion for comparison. The results showed that the corrosion initiation periods obtained experimentally were comparable to those obtained empirically. The corrosion initiation was found to occur at the first jump of the current measurement in the accelerated corrosion test which matched the half-cell potential reading of around −350 mV.

Pressure and temperature dependence of acoustic wave speeds in bitumen-saturated carbonates: Implications for seismic monitoring of the Grosmont Formation

Geophysics ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. MR133-MR151 ◽  
Author(s):  
Arif Rabbani ◽  
Douglas R. Schmitt ◽  
Jason Nycz ◽  
Ken Gray
Keyword(s):  
Oil Recovery ◽  
Oil Sands ◽  
Saturation Pressure ◽  
Time Lapse ◽  
S Wave ◽  
Heated Sample ◽  
Wave Speeds ◽  
Seismic Reflectivity ◽  
Water Saturated ◽  
Northern Alberta

Recent time-lapse seismic observations in carbonate reservoirs subject to steam-assisted enhanced oil recovery display substantial changes in seismic reflectivity due to the combined effects of saturation, pressure, and temperature. Understanding these field seismic observations requires knowledge of the effects on the seismic wave speeds in bitumen-saturated carbonates. We have conducted ultrasonic measurements of P- and S-wave velocities in bitumen-saturated dolomite taken from the Grosmont Formation in northern Alberta. Wave speeds are measured under a variety of conditions of constant pore pressure, constant effective pressure, and with varying temperature to map the various controlling factors. The temperature-dependent declines of 12% and 9% for the P- and S-wave speeds, respectively, with temperatures from 10°C to 102°C are most notable. Unlike oil sands, at times, the dolomite retains its structure upon removal of the bitumen allowing for measurement of the dry and water-saturated frame properties and their subsequent use in substitutional modeling. None of the standard bounding, inclusion, or Biot-Gassmann family models adequately describe the observations in the heated sample. The deviations may be in part due to the inability of these models to properly incorporate the complex bitumen non-Newtonian rheology including a bulk viscosity.

The influence of confining pressure and water saturation on dynamic elastic properties of some Permian coals

Geophysics ◽  
1993 ◽  
Vol 58 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Gang Yu ◽  
Keeva Vozoff ◽  
David W. Durney
Keyword(s):  
Elastic Properties ◽  
Water Saturation ◽  
Elastic Anisotropy ◽  
Confining Pressure ◽  
S Wave ◽  
Bedding Planes ◽  
Confining Pressures ◽  
Mine Development ◽  
Water Saturated ◽  
Dynamic Elastic Properties

Laboratory measurements are described on Permian coals from Wollongong, New South Wales, Australia related to the dependence of ultrasonic P‐ and S‐wave velocities, attenuation, anisotropy and the dynamic elastic moduli on confining pressure, water saturation, and pore pressure. Five independent stiffness constants are used to represent the elastic anisotropy of the specimens as a function of confining pressure and water saturation. The anisotropy is believed to be controlled mainly by the internal structure of the coals, while the pressure dependence of the constants is controlled mainly by randomly oriented cracks. P‐ and S‐wave dispersions were measured on water‐saturated specimens as confining pressures increased from 2 MPa to 40 MPa. The samples represented cores taken both parallel and perpendicular to bedding planes. Velocities along bedding planes are marginally higher than those across bedding planes. This anisotropy is insensitive to confining pressure. Attenuation was also measured, both normal and parallel to bedding planes, on dry and water‐saturated specimens from 2 MPa to 40 MPa confining pressures. The experimental results show that dynamic elastic properties are potential indicators of the states of stress and saturation in coal seams, and provide necessary information for computer modeling and interpreting seismic surveys carried out to assist mine development.

scholarly journals Effectiveness of in situ P-wave measurements in monuments: examples from Greece

2000 ◽  
Vol 22 ◽  
Author(s):  
B. Christaras
Keyword(s):  
Modulus Of Elasticity ◽  
Building Stone ◽  
P Wave ◽  
Mechanical Anisotropy ◽  
Laboratory Measurements ◽  
S Wave ◽  
Wave Velocities ◽  
Wave Measurements ◽  
Made In

P and S wave velocities can be used for both in situ and laboratory measurements of stones. These methods are used for studying such properties as mechanical anisotropy and modulus of elasticity. In this paper, the P-wave velocities were used for the estimation of the depth of weathered or artificially consolidated layers as well as the depth of cracks developed at the surface of the building stone. This estimation was made in relation to the lithology and texture of the materials, given that in many cases different lithological data create similar diagrams. All tests were carried out on representative monuments in Greece.

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