Strength And Related Properties Of Concrete A Quantitative Approach PdfBy Quiteria G. In and pdf 13.05.2021 at 13:24 9 min read
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Science and Technology of Materials is the official journal of SPM, the Portuguese Society of Materials Sociedade Portuguesa de Materiais , providing a forum for publishing peer-reviewed papers related to both fundamentals of materials science and technological application of engineering materials.
Click here to check the full schedule: Library Complete Schedule. Quantitative research focuses on gathering numerical data and generalizing it across groups of people or to explain a particular phenomenon. The final written report has a set structure consisting of introduction, literature and theory, methods, results, and discussion. Babbie, Earl R.
Systems Analysis And Design Methods 7th Edition Solution Manual Pdf
Science and Technology of Materials is the official journal of SPM, the Portuguese Society of Materials Sociedade Portuguesa de Materiais , providing a forum for publishing peer-reviewed papers related to both fundamentals of materials science and technological application of engineering materials. The scope of the journal covers a wide range of topics in materials science that are of interest to the SPM, encompassing electrochemistry, corrosion and protection of materials, extractive metallurgy and recycling, electronic and optoelectronic materials, biomaterials, forest materials, polymeric and composite materials, foundry, heat treatment and surface engineering, tribology, and fracture.
Science and Technology of Materials welcomes contributions in the form of original research papers, review articles and technical notes reporting advances on those fields, emphasizing new materials, new products and devices, and new technologies. CiteScore measures average citations received per document published.
Read more. SRJ is a prestige metric based on the idea that not all citations are the same. SJR uses a similar algorithm as the Google page rank; it provides a quantitative and qualitative measure of the journal's impact.
SNIP measures contextual citation impact by wighting citations based on the total number of citations in a subject field.
Preparation process and life service solicitations can cause damage on concrete's internal structure, creating cracks that tend to propagate and increase with time. This poses a risk of failure as water penetrates, corroding the rebar reducing concrete's life span. Cement can exhibit up to a certain extent a natural ability to self-heal, consequence of the long-term hydration phenomenon. Some initial cracks can be spontaneously closed if the right conditions are met humidity.
However, it will not be enough to repair major cracks formed internally over a long period of use, so strategies need to be developed to achieve an efficient level of self-healing. This need lead to a new concept — self-healing.
The biological approach is a suitable alternative to achieve healing in concrete. In this work, bacteria were immobilised in expanded clay and added to concrete by aggregate replacement.. Sustainability has been a key driving force within construction in recent years. Non-renewable natural resources i.
The onus on construction industry to deliver projects that meets high quality standards and sustainability criteria are extremely high. The construction sector has taken steps to minimise the use of non-renewable materials and one of these materials is concrete [3,4].
This unique material has been used for more than one century and the development of concrete has come a long way since. Many variations have been trialled throughout the years to understand, and expand upon, its use. Today, it is usually made up of four main constituents — binder, aggregate, water and admixtures. To increase the strength of concrete, generally more cement needs to be included. Large strides have been made in turning concrete into a more sustainable material .
Concrete has many qualities, ranging from its high strength and ability to withstand natural disasters, to its versatility and low maintenance. It is because of these many qualities that concrete remains an essential component when it comes to construction design, however its high susceptibility to crack remains unsolved, .
Structural failure of concrete has been one major concern in industry. The standard approach has been to prepare stronger concrete, a non-sustainable solution with high environmental impact. Search for a more sustainable and durable concrete, less prone to cracking, lead to a new concept — self-healing [7,8].
This concept, inspired by the natural ability of plants and human skin to spontaneously heal, inspired researchers to search for a method of conferring concrete with the ability to self-repair internal damage . This poses a potential risk of failure as water infiltrates and allows for chloride ion penetration, corrosion of the rebar, amongst other problems — considerably reducing concrete's life span.
It is known that cement can exhibit, up to a certain extent, a natural ability to self-heal, a consequence of the long-term hydration phenomenon. Hence, some initial cracks can be spontaneously closed if the right conditions are met — concrete's incomplete saturation, presence of residual clinker and crystallisation of calcium carbonate . This, however, will not be enough to repair most of the major cracks that are formed internally over a long period of use, so strategies need to be developed to achieve an efficient level of self-healing.
The development within this field has led to the investigation of different routes. Promoting continuing hydration using admixtures [13,14].
Use of encapsulated healing agents . Use of shape memory materials SMM . Chemical and biological self-healing involves the addition of an extra element, not included in the original mix design.
This additive triggers a reaction mechanism and products from the process are responsible for the crack closure. The biological approach has been presented as a suitable alternative to achieve healing in concrete and it is the one presented and discussed in this research work . Jonkers describes the mechanism of adding bacteria to concrete, a process that through the addition of ingress water, allows the conversion of calcium lactate to calcium carbonate limestone which results in the crack sealing Fig.
Due to the high PH level conditions found within concrete, the bacteria infused within the structure can remain dormant for, depending on the type of strain, years . It is only when cracks start to form and water seeps in, that PH lowers and the bacteria are activated . Self-healing mechanism in bacteria concrete.
The CaCO 3 limestone compound can, not only be formed through the natural process, but also through this microbial metabolic operation. This formation can be directly related to a human biological feature, the repairing of bone post-fracturing. However, selecting the bacteria that will be most effective is a demanding task.
When conducting research into finding the correct bacteria, scientists initially had to find a species that had the capability of being able to endure high alkaline conditions. When water and cement combine, they create a PH level that can reach as high as For many bacteria, and organisms alike, this type of environment is too harsh to survive. Results showed that a certain strain of bacteria, namely Bacillus , seemed to flourish in notably severe conditions [19,20]. In addition, it is not only the sourcing of viable bacteria that scientists have been trying to uncover but also acquiring a convenient food source.
The food source that is required, not only has to be relevant to the specific bacteria at hand, but also has to last a long time within the concrete before the bacteria become active . Numerous experiments on its use have found a significant increase in compressive strength, post-cracking, in comparison to controls groups . Furthermore, it is noted that the limestone created via this process, may increase the concrete resistance to free—thaw cycles, preventing any future cracks that may arise.
Another potential advantage is that the permeability of the structure will also decrease and corrosion of reinforced concrete will be lower, as the limestone will seal routes for further water ingress to occur [24,25]. The process does have some constraints though. This addition of large quantities of bacteria will bring a cost; in some case almost double that of conventional concrete [22,26].
The two main approaches to harbouring the immobilised bacteria within the concrete are the use of expanded clay and encapsulation in polymers.
Jonkers et al. The clay would encapsulate the bacteria and conceal it for an extended length of time. In order to introduce the expanded clay, some, or all, of the aggregate would be replaced within the concrete, depending on the type of concrete required. This change in aggregate would lower the overall compressive strength of the concrete, due to the more hardened and dense gravel being lost. Nevertheless, even with the initial loss in compressive strength, it was found that the autonomous healing of the substrate greatly outweighed that of the gravel compound.
The process seems feasible and the dispersion of the clay throughout the entire concrete mix proved to be possible. However, the even distribution of the clay particles still needs to be addressed, along with the ability of clay to withstand heavy forces during the mixing and pouring of industrial-sized quantities. The capsule method follows the same principle as with the aforementioned encapsulation in expanded clay. The healing agent is contained by the capsule membrane and will only be released when a crack has penetrated the capsule wall .
Unlike the clay, the capsules are an additive rather than a replacement for any of the major constituents. This therefore allows the initial compressive strength of the concrete, pre-crack, to remain high as the gravel aggregate will still be included.
The encapsulation of bacteria within the capsule is not an easy process, in comparison to the expanded clay. Specialised laboratory equipment is required, which in turn brings its own additional costs. This would give a water cement ratio of 0. The expanded clay used was Liapor with a particle size between 1 and 4 mm, supplied by Weber. Composition for the concrete with expanded clay and bacteria.
Next the expanded clay was added and manually mixed,. The water was added in stages, to ensure all components were bound well within the mix, during mechanical mixing for 2 min. To keep consistency, when casting all mixes, they were subsequently placed on the vibrating table for 30 s to even out the distribution within the mould.
The alkali-resistant bacteria selected derives from alkaliphilic bacteria of the genus Bacillus and organic mineral compounds. The preparation of the expanded clay with bacteria has followed the method previously described by Tziviloglou et al.
Calcium lactate, yeast extract and bacteria spores were impregnated under vacuum in particles of expanded clay. The clay was then dried until reach a constant weight. Compression testing was carried out using an Avery Denison testing machine type CB calibrated in accordance with BS Part Load was applied at the rate of 2.
Before starting with the self-healing tests, it was necessary to determine the compression strength of a group of control samples to establish the force required to cause microcracks into the concrete samples. A trial group of samples was tested until failure reaching an average compression force of This was the force applied to pre-damage the samples before healing. These samples where then tested to failure after 7, 28, 56 and 63 days of healing.
A group of control samples containing expanded clay without bacteria was also damaged and tested after the same healing intervals. The assessment and quantification of healing has been one of the most challenging and important aspects in these materials.
Different authors have explored diverse methods and no standard process has been made available so far . Self-healing in this work was determined following the equation: where F c is the compression strength for the control sample and F h is the compression strength for the healed sample.
Concrete containing bacteria encapsulated in expanded clay shows an increase in the compressive strength after only 7 days of healing Figs. When the results are compared with the control samples it is clear that the strength increase is caused by the presence of bacteria in the expanded clay. The samples containing solely expanded clay, without bacteria, show some improvement in mechanical strength from 7 to 28 days — which is expected from the normal hydration process of concrete — followed by practically constant strength after this period, when it reaches a plateau.
Average compressive strength after healing. Healing efficiency compared with standard concrete.
[PDF Download] Strength and Related Properties of Concrete: A Quantitative Approach [Read]
This paper deals with the interfacial effects of silica fume SF and styrene-butadiene rubber SBR on compressive strength of concrete. Analyzing the compressive strength results of 32 concrete mixes performed over two water—binder ratios 0. This understanding model might serve as useful guides for commixture concrete admixtures containing of SF and SBR. The accuracy of the proposed model is investigated. Good agreements between them are observed. Compressive strength of concrete is affected by many factors, such as cement composition and fineness, water-to-cement ratio, aggregate, age and temperature of curing. There is as yet no such formula mathematical model that could reproduce the effects of all these factors adequately in a quantitative manner, primarily due to a high number of variables Zelic et al.
The editors of the Landscape Irrigation Design Manual hope such an opportunity is available to you and that the information presented here is of benefit. The official controlled copy of this quality manual is the digitally signed PDF document held within our network. I decided to user jasper report tool for my reports. This system is aimed to improve vehicle performance on all terrain conditions from rough to flat surfaces. News, email and search are just the beginning. Software Engineering: A Practitioner's Approach, seventh edition by Roger Pressman—the next edition of the world's best selling software engineering textbook.
Once production of your article has started, you can track the status of your article via Track Your Accepted Article. An international journal dedicated to the investigation and innovative use of materials in construction and repair. Construction and Building Materials provides an international forum for the dissemination of innovative and original research and development in the field of construction and building materials Construction and Building Materials provides an international forum for the dissemination of innovative and original research and development in the field of construction and building materials and their application in new works and repair practice. The journal publishes a wide range of innovative research and application papers which describe laboratory and to a limited extent numerical investigations or report on full scale projects. Multi-part papers are discouraged.
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Cement industry consumes high energy and produces major emissions to the environment. In order to reduce the effects environmental impact, energy, and resources caused by conventional materials, various by-products and pozzolonic material are used to achieve sustainable concrete. Assessing the concrete performance based on multiple conflicting attributes is decisive and compelling.
The point load strength I s 50 is an alternative mechanical parameter to predict the compressive strength of concrete. The scope of this investigation is to develop an empirical equation relating the point load strength and compressive strength of concrete. In this context, crushed limestone aggregates at two different strength levels were used in concrete mixture.
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The science and technology of concrete have been based almost exclusively on empirical knowledge. The description of concrete properties and behavior was therefore by necessity mostly of qualitative nature. The author, a recognized expert in the field, has attempted to present a very special state-of-the-art report in such a way that it can point in the direction of rationalizing the theory.
Corrosion of steel rebar in reinforced concrete is one the most important durability issues in the service life of a structure. In this paper, an investigation is conducted to find out the relationship between the amount of reinforced concrete corrosion and GPR maximum positive amplitude. The corroded rebars were then placed into three different oil emulsion tanks having different dielectric properties similar to concrete. The maximum amplitudes from the corroded bars were recorded.
The increasing number of early deterioration symptoms found in relatively new concrete structures provides a strong argument for the development and validation of techniques to monitor the condition state of concrete elements and provide data to estimate the potential service life. The use of NDT monitoring techniques is an important way to prevent and control the deterioration of concrete structures without damaging the material. Using UPV data it is possible to check the concrete uniformity, accompany the deterioration, detect internal flaws and voids and, by means of a comparison with reference specimens, even estimate the compressive strength.
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Popovics Published Materials Science. This book addresses concrete strength.
There is no standardized procedure for producing geopolymers; therefore, many researchers develop their own procedures for mixing and curing to achieve good workability and strength development. The curing scheme adopted is important in achieving maximum performance of resultant geopolymers. In this study, we evaluated the impact of sealed and unsealed curing on mechanical strength of geopolymers. Fly ash-based geopolymers cured in sealed and unsealed moulds clearly revealed that retention of water during curing resulted in superior strength development.
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