scholarly journals Assessment of Long Lived Isotopes in Alkali-Silica Resistant Concrete Designed for Nuclear Installations

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4595
Author(s):  
Daria Jóźwiak-Niedźwiedzka ◽  
Katalin Gméling ◽  
Aneta Antolik ◽  
Kinga Dziedzic ◽  
Michał A. Glinicki
Keyword(s):  
Portland Cement ◽  
Nuclear Reactor ◽  
Neutron Radiation ◽  
Radiation Shielding ◽  
Alkali Silica Reaction ◽  
Portland Cement Concrete ◽  
River Sand ◽  
Activation Cross Section ◽  
Coarse Aggregates ◽  
Selection Of

The design of concrete for radiation shielding structures is principally based on the selection of materials of adequate elemental composition and mix proportioning to achieve the long-term durability in nuclear environment. Concrete elements may become radioactive through exposure to neutron radiation from the nuclear reactor. A selection of constituent materials of greatly reduced content of long-lived residual radioisotopes would reduce the volume of low-level waste during plant decommissioning. The objective of this investigation is an assessment of trace elements with a large activation cross section in concrete constituents and simultaneous evaluation of susceptibility of concrete to detrimental alkali-silica reaction. Two isotopes 60Co and 152Eu were chosen as the dominant long-lived residual radioisotopes and evaluated using neutron activation analysis. The influence of selected mineral aggregates on the expansion due to alkali-silica reaction was tested. The content of 60Co and 152Eu activated by neutron radiation in fine and coarse aggregates, as well as in four types of Portland cement, is presented and discussed in respect to the chemical composition and rock origin. Conflicting results were obtained for quartzite coarse aggregate and siliceous river sand that, despite a low content, 60Co and 152Eu exhibited a high susceptibility to alkali-silica reaction in Portland cement concrete. The obtained results facilitate a multicriteria selection of constituents for radiation-shielding concrete.

Development of Low-Activation Design Method for Reduction of Radioactive Waste Below Clearance Level

2008 ◽  
Author(s):  
Ken-Ichi Kimura ◽  
Akira Hasegawa ◽  
Katsumi Hayashi ◽  
Mikio Uematsu ◽  
Tomohiro Ogata ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Portland Cement ◽  
Power Plants ◽  
Raw Materials ◽  
Development Project ◽  
Radiation Shielding ◽  
Benchmark Calculation ◽  
Steel Bars ◽  
Clearance Level ◽  
Selection Of

Design methodology for reinforced concrete of nuclear power plants to reduce radioactive wastes in decommission phase has been developed. To realize this purpose, (1) development of raw materials database of cements, aggregates and steel bars on concentration of radioactive target elements, (2) trial production of low activation cements and steel bars based on the material database developed in (1), and (3) development of tools for estimation and prediction of the amount of radioactive elements in reactor shielding walls have been carried out. Radioactive analysis showed that Co and Eu were the major target elements which decide the radioactivity level of reinforced concrete from wide survey of raw materials for concrete (typically aggregates and cements). Material database for the contents of Co and Eu was developed based on the chemical analysis and radioactivation analysis. Upon the above survey and execution expreiment of concrete, six types of low-activation concrete are proposed for various radioactive portion in the plant. These concrete have a 1/10 – 1/300 rasioactivity compare to the ordinary concrete, which are assumed the concrete with Andesite aggregate and ordinary Portland cement. Baed on the above data base, it was clarified that the low activation cement would be successfully manufactured by adequate selection of raw materials. The prospect to produce the low-heat portland cement which would have a 1/3 radioactivity in comparison with conventioanl cements obtained by means of selection of limestone and natural gypsum. An attempte was carried out to produece low activation heavy-mortar which would have radioactivity below the clearance level when using at the radiation shielding wall of BWR. Characterization and optimization of consturction conditions with new additives have also been carried out. These two new raw materials for low-activation concrete are conducted in pre-manufacture size, and over the laboratry level. Boron added low-activation concrete are also carried out as extreamly high performance low-activation concrete. It was claryfied that the accurcy of calculation results of the radioactivity evaluation was very high compared to available benchmark calculation for the JPDR and commercial light water reactor. The specification of the mapping system for judging the activation classification was also developed by using the general-purpose radio activation calculation tool. This work is supported by a grant-in-aid of Innovative and Viable Nuclear Technology (IVNET) development project of Ministry of Economy, Trade and Industry, Japan.

Implementation Feasibility of Asphalt Concrete–Overlaid Portland Cement Concrete Pavement Rehabilitation Guidelines

1997 ◽  
Vol 1568 (1) ◽  
pp. 155-164
Author(s):  
Kathleen T. Hall ◽  
Amy Schutzbach
Keyword(s):  
Portland Cement ◽  
Asphalt Concrete ◽  
Concrete Pavements ◽  
Remaining Life ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Pavement Rehabilitation ◽  
Cement Concrete Pavement ◽  
Rehabilitation Strategy ◽  
Selection Of

Illinois Highway Research Study IHR-532 was conducted to develop project-level guidelines for evaluation, rehabilitation selection, and rehabilitation design for existing asphalt concrete–overlaid portland cement concrete (AC/PCC) pavements in Illinois. Use of these guidelines depends on data that are not normally available for network-level analysis. A study was conducted to assess the feasibility of implementing these guidelines in network-level decision making and to assess the effects that implementing these guidelines for selection of rehabilitation methods for existing asphalt-overlaid concrete pavements would have on the overall rehabilitation budget requirements for a district network of Interstate pavements, the overall network condition, and pavement network remaining life. These objectives were met by comparing the IHR-532 rehabilitation strategy (which identifies one or more rehabilitation options) with the Illinois Department of Transportation’s current rehabilitation policy, which is an AC overlay thickness of 83 mm (3.25 in.). This feasibility analysis indicated that the selection of the preferred rehabilitation strategy was strongly related to the type and condition of the existing pavement. It also indicated that the IHR-532 rehabilitation strategy and the single rehabilitation strategy yielded similar networkwide results when compared on the basis of average condition at the end of the analysis period. However, the IHR-532 rehabilitation strategy indicated greater benefit than the single rehabilitation strategy, at any budget level, when compared on the basis of network average remaining life at the end of the analysis period.

Effects of coarse aggregates on the electrical resistivity of Portland cement concrete

2017 ◽  
Vol 133 ◽  
pp. 397-408 ◽  
Author(s):  
Tsung-Chin Hou ◽  
Van Kien Nguyen ◽  
Yu-Min Su ◽  
Yuan-Rong Chen ◽  
Pei-Ju Chen
Keyword(s):  
Electrical Resistivity ◽  
Portland Cement ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Coarse Aggregates

scholarly journals Influence of Selected Curing Techniques on Compressive Strength of Concrete From Palm Kernel Shell Ash and Ordinary Portland Cement

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
Oluwatosin Babatola
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Palm Kernel ◽  
Maximum Size ◽  
Portland Cement Concrete ◽  
River Sand ◽  
Palm Kernel Shell ◽  
Crushed Aggregate ◽  
Compressive Strength Of Concrete

This paper discusses the findings of an experimental study on the effect of various curing procedures on the compressive strength of concrete produced by partially substituting portland cement with Palm Kernel Shell Ash (PKSA). Palm kernel shell ash was utilized in a 1:2:4 mix ratio as a partial substitute for ordinary Portland cement (OPC) at percentage levels of 0%, 10%, and 15%. River sand with particles passing a 4.75 mm BS sieve was used, as well as crushed aggregate with a maximum size of 20 mm, and palm kernel shell ash with particles passing a 212 μm sieve. The compressive strength of the test cubes (150 mm x 150 mm x 150 mm) was determined after 7, 28, and 56 days of curing. The results demonstrated that test cubes containing Palm kernel shell ash developed strength over a longer curing period than ordinary Portland cement concrete samples and that the strength changes depending on the amount of PKSA in the cube samples. The findings showed that at 28 days, test cubes with 5%, 10%, and 15% PKSA content in all curing procedures utilized obtained a greater compressive strength. Curing by immersion produced the highest compressive strength in all replacement level while the concrete cured by sprinkling and spraying gives a lower strength in all replacement leve

scholarly journals Influence of Cement Replacement with Fly Ash and Ground Sand with Different Fineness on Alkali-Silica Reaction of Mortar

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1528
Author(s):  
Suwat Ramjan ◽  
Weerachart Tangchirapat ◽  
Chai Jaturapitakkul ◽  
Cheah Chee Ban ◽  
Peerapong Jitsangiam ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Partial Substitution ◽  
Alkali Silica Reaction ◽  
Inert Material ◽  
Fly Ashes ◽  
River Sand ◽  
Concrete Materials

The alkali-silica reaction (ASR) is an important consideration in ensuring the long-term durability of concrete materials, especially for those containing reactive aggregates. Although fly ash (FA) has proven to be useful in preventing ASR expansion, the filler effect and the effect of FA fineness on ASR expansion are not well defined in the present literature. Hence, this study aimed to examine the effects of the filler and fineness of FA on ASR mortar expansion. FAs with two different finenesses were used to substitute ordinary Portland cement (OPC) at 20% by weight of binder. River sand (RS) with the same fineness as the FA was also used to replace OPC at the same rate as FA. The replacement of OPC with RS (an inert material) was carried out to observe the filler effect of FA on ASR. The results showed that FA and RS provided lower ASR expansions compared with the control mortar. Fine and coarse fly ashes in this study had almost the same effectiveness in mitigating the ASR expansion of the mortars. For the filler effect, smaller particles of RS had more influence on the ASR reduction than RS with coarser particles. A significant mitigation of the ASR expansion was obtained by decreasing the OPC content in the mortar mixture through its partial substitution with FA and RS.

Experimental investigations on compressive, impact and prediction of stress-strain of fly ash-geopolymer and portland cement concrete

2020 ◽  
Vol 40 (7) ◽  
pp. 583-590
Author(s):  
Nagajothi S ◽  
Elavenil S
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Impact Resistance ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Stress Strain ◽  
River Sand ◽  
Conventional Concrete ◽  
Strain Behaviour

AbstractThe recent technology of geopolymer concrete is a substitute material for ordinary portland cement concrete which is produced from the polycondensation reaction of aluminosilicate materials with alkaline activator solutions. The cost of river sand is high since the demand for the same is also high. Manufactured sand is used as a replacement material for river sand in geopolymer concrete. This paper mainly focuses to find the properties of fly ash (FA) – based geopolymer concrete under ambient cured temperature like compressive strength, stress strain behaviour, modulus of elasticity, Poission’s ratio and impact resistance. The result of geopolymer concrete is compared with ordinary portland cement concrete. The elasticity modulus and Poission’s ratio of geopolymer concrete are lower than conventional concrete. The Stress-strain behaviour of geopolymer concrete is similar to conventional concrete. The impact resistance of geopolymer concrete is very good when compared with conventional concrete.

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