The Effect of Concrete

The attack leaves more or less grey traces on the surface of the metal, which is why aluminium needs to be protected against splashing of concrete and roughcast if its appearance is to be preserved. 

Prolonged contact with concrete, even in the presence of humidity, leads only to a superficial attack, shown by testing results with concrete blocks with embedded unprotected aluminium (Table G.4.1) that were exposed to various media, including marine atmosphere [3]. The zone of emergence in the air is not prone to corrosion (see Section B.2.7). 

Anodising layers do not resist alkaline media they are dissolved during the setting of concrete and therefore do not improve the resistance of aluminium in contact with concrete [4]. 

It is common to add up to 3% calcium chloride to concrete, in order to accelerate setting and thus avoid freezing in the cold of winter. This leads to a substantial decrease in the resistivity of concrete adding 3% calcium chloride leads to a drop in resistivity by a factor of 1000. Since calcium chloride is hygroscopic, it may keep the concrete from drying. In the presence of humidity, the conductivity of the medium increases, and electrical corrosion reactions are facilitated. In the absence of humidity, stray currents and contact with steel, adding chlorides does not significantly modify the resistance of aluminium in concrete [7]. 

Experience has shown that adding up to 0.5% calcium chloride does not modify the resistance of aluminium. 

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In most chemical occupancies, the preparation of floors and the coating formulation to be used are not straightforward decisions. Research which has been conducted on the effectiveness of concrete coatings and offers more information on these issues than do current government... 

The rate of cracking and spalling of the concrete when exposed to the expansion forces of the corrosion products. The effect of concrete properties on the corrosion and concrete deterioration processes of bridge structures has been... 

Concrete slabs prevent that a pipeline is hit during digging activities. The effectiveness of concrete slabs and warning tapes is derived from experiments. In about 50 tests excavators were asked to excavate a deep foundation on sites were actually pipelines with concrete slabs were buried. They were not irfformed the pipeline was present at that site. By determining the reaction of the excavator the factors as given in Table 1 could be derived (Corder 1995). 

There are now a number of inhibitors being offered to improve the effectiveness of concrete repairs. They can be applied as coatings on the surface or on to the exposed steel at patch repairs, incorporated into the patch repairs, applied in grooves or drilled holes in the concrete cover or incorporated into concrete overlays. 

The presence of boron In concrete has been recognised as a means of improving the effectiveness of concrete as a neutron shield and reducing its activity level . By using non-soluble boron frits, researchers in Japan have succeeded in producing concrete mixes with a boron content of up to 6.4%. 

The response of foe array multiplication factor to changes in the radius of the units was explored and furnishes an internally consistent relationship allowing prescribed minimum reactivity adjustments to be made for environmental conditions Jn this way margins of safety arc e iq)resslble in terms of foe array reactivity. For example, the effects of. concrete as a reflector of an array and its Influence on neutron coupled arrays were investigated for several thicknesses of concrete. Also,... 

Considerable effort was concentrated on evaluating the effect of concrete composition on k Q for the storage array. Local concrete is high in basalt and low in limestone (carbon). The differences in aggregates used for ordinary concrete were found to change keff by as much as 250 mllli-k between extremes. 

A study of the effects of concrete and plastic enclosures around single and multiple vessel arrays containing enriched U02(N0s)2 solutions. The results of Uiese measurements will be valuable in determining the adequacy with which current criticality codes evaluate the neutron reflector properties of ccmcrete and plastic. 

Then to determine the effect of concrete on the radius of coverage, Eqs. (1) and (2) can be combined to give... 

Concrete Shrinkage Concrete shrinkage effect can be simulated by applying volumetric strain to the elements of the jacket. The effect of concrete creep should also be included to take into account the tensile stress relaxation. In a previous study (Lampropoulos and Dritsos 2010), in order to include creep effects, application of a volumetric strain equal to half of the free concrete shrinkage strain was proposed. 

N. Dobbs and co-workers, "Design of Steel, Masonry and Precast Concrete Stmctures to Resist the Effects of HE Explosions" in 17th Annual Dept, of Defense Explosive Safety Seminar,NT S, Springfield, Va., 1976. 

Harbor structures are very accessible and can be investigated without the effects of wave motion. Grounding of steel pilings presents no problems and the work can be carried out from the quay (see the left-hand side of Fig. 16-13). With steel-reinforced concrete structures, measurements have to be made from a boat if no reliable contact has been provided in their eonstruction (see the right-hand side of Fig. 16-13). 

Since stray current corrosion damage can occur after only a few years, the economy of stray current protection measures is obviously not questionable [12], In Fig. 22-3 the effect of stray currents is shown by curve 2 [14]. Without there being firm evidence, it is apparent that the shape of the corrosion damage curve in steel-reinforced concrete (see Sections 10.3.6 and 4.3) is similar to that for stray current corrosion [15]. 

At Qatar, the liquid came out with such force that it spilled over the dike wall. Conventional dike walls also have the disadvantage that a large area of liquid is exposed to the atmosphere if a leak occurs. For these reasons it is now usual to surround cryogenic storage tanks with a concrete wall, about 1 m from the tank and the full height of the tank. If the tank is not made from crack-resistant material, then the concrete wall should be designed to withstand the effects of a sudden release of liquid. 

Calculate the beating due to solar radiation on the flat concrete roof of a building, 8 nr by 9 m. if the surface temperature of the roof is 330 K. What would be the effect of covering the roof with a highly reflecting surface such as polished aluminium ... 

In another concrete example of use, the Ugi reaction served as a prominent example to test the performance of one micro mixer and to test specifically the effect of micro mixing on such a multi-stage reaction [25]. 

R. G. Buchheit, T. E. Hinkebein, R F. Hlava, and D. G. Melton. The effects of latex additions on centrifugally cast concrete for internal pipeline protection. In Proceedings Volume, volume 4, pages 2854-2864.12th SPE/NACE Int Corrosion Congr (Houston, TX, 9/19-9/24), 1993. 

Mortar specimens were prepared to determine the effectiveness of MRI in a time resolved lithium penetration experiment [15]. This work used a non-reactive aggregate and commercially available LiN03 solution to simulate topical treatments to concrete. These results will aid the development of a more general measurement of concrete core extracted from a lithium treated structure suffering from ASR. 

Hogan, F.J., The effect of blast furnace slag cement on alkali aggregate reactivity a literature review, Cement Concrete and Aggregates, 7, 2, 1985. 

The internal walls between the scullery and the office and between the kitchen and the sitting room descended below the base of the concrete floor to the sub-soil. Clearly, the effectiveness of the suction systems in reducing the soil gas concentration at the base of the walls was limited because of the distance from the suction points. 

In the past, it was thought that building materials were the principal sources of indoor radon (UNSCEAR, 1977). However, most recent studies have shown that with the exception of some unusual materials such as Swedish alum-shale concrete, the effect of building materials on indoor radon is small. 

The exact Eq. (4.2.17) takes into account the effect of the reservoir (the condensed phase) on the spectral line shape through the parameter 77. Consideration of a concrete microscopic model of the valence-deformation vibrations makes it possible to estimate the basic parameters y and 77 of the theory and to introduce the exchange mode anharmonicity caused by a reorientation barrier of the deformation vibrations thereby, one can fully take advantage of the GF representation in the form (4.2.11) which allows summation over a finite number of states. 

The advantages of using reinforced concrete for the design of blast-hardened structures and the important recent changes to the design criteria of flexural elements have been summarized. Detailed design of hardened structures should be in accordance with the criteria in the tri-service design manual, TM 5-1300/NAVFAC P-397/AFM 88-22, "Structures to Resist the Effects of Accidental Explosions". 

The most-abstract actions represent only the effect of an interaction. The more-detailed ones are directional, stating who intiates the request and who processes it. The most-concrete actions are object-oriented messages. 

Normally, the effects of missile impact and penetration on buildings are not considered in detail. It is difficult, if not impossible, to predict the size and velocity of projectiles. Usually a concrete wall will prevent the penetration of most projectiles. A neutral risk philosophy does not consider the effects of external projectiles. 

Figure 5.2 illustrates the effectiveness of an underground shelter to limit radiation dose. In the open, an individual will receive an unshielded radiation dose (D). If the individual is in a deep hole with only a thin overhead cover (e.g., plywood), the dose level drops by about a factor of ten (D/10). While this is better than being in an open area, fatal doses might still be received. If the cover is made of about one foot of concrete, the dose level drops by a factor of about 100 (D/100). Two feet or more of concrete will reduce dose levels by a factor of about 5000 (D/5000).2... 

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