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Analyzing the Beam's Deformation Behavior on an Elastoplastic Foundation
Emmanuel Emeka Arinze,
Emeka Ogbonnaya Oti
Issue:
Volume 7, Issue 4, August 2022
Pages:
40-45
Received:
10 June 2022
Accepted:
23 June 2022
Published:
5 July 2022
DOI:
10.11648/j.jccee.20220704.11
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Abstract: The idea of beams on elastic foundation has been widely applied in the design of geotechnical structures such railway tracks, rigid and flexible highway pavement, building and habour structures. Winkler was the first to present the analysis of a beam on an elastic foundation for the analysis of railroad track deflection, based on the premise that the foundation reaction forces are proportionate to the deflection of the beam at that location. An elastic material regains its original shape on unloading whereas plastic material do not; an elastoplastic material undergoes coupled elastic (recoverable) and plastic (unrecoverable) deformations during loading and unloading. Soils are really elastoplastic material. At stresses below the yield stresses soil to responds elastically, whereas at stresses beyond yield stress soil to respond elastoplastically. The conventional analysis of plate on elastic foundation is inadequate which necessitated this study. This study focuses on the analysis of a beam on an elastoplastic foundation. Though the derivation started with winkler’s model, elastoplastic condition was considered. It was also assumed that the soil is homogeneous and isotropic; and that the beam on elastoplastic system is symmetrical with law of superposition applying. The derivation was further confirmed using Buckingham Pi theorem for dimensional analysis.
Abstract: The idea of beams on elastic foundation has been widely applied in the design of geotechnical structures such railway tracks, rigid and flexible highway pavement, building and habour structures. Winkler was the first to present the analysis of a beam on an elastic foundation for the analysis of railroad track deflection, based on the premise that t...
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Strength Prediction and Optimization of Saw Dust Ash-Eggshell Cement Blends Using Response Surface Methodology
Olubajo Olumide Olu,
Ibrahim Abuthakir,
Jarumi Luka
Issue:
Volume 7, Issue 4, August 2022
Pages:
46-62
Received:
26 May 2022
Accepted:
23 June 2022
Published:
13 July 2022
DOI:
10.11648/j.jccee.20220704.12
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Abstract: The necessity to overcome the challenge of cumbersome and time-wasting technique of strength determination of cement blends. Several avenues are been exploited in prediction of the mortar compressive strength of ternary cement blended comprising saw dust ash (SDA) and eggshell powder (ESP). The strength gains of the cement blends were determined and monitored based on factors like saw dust ash content, curing age and replacement level. The purpose of this research was to evaluate on the influence of saw dust ash with eggshell powder content, replacement level and curing age on the mortar strength using Box & Behnken (BBD), Central Composite (CCD) and Three Level Factorial (3FD) designs. Comparison of the various models was be conducted to ascertain the model with the best strength prediction. Optimization of the process conditions were also evaluated to obtain the optimal strength of the cement blends using response surface methodology. Analysis of variance (ANOVA) results showed that the experimental data satisfied second order polynomial regression model for all three models. An increase in SDA/SDA-ESP ratio and curing age both independently or simultaneously led to an increase in the mortar strength of various cement blends using 3FD and BBD models with the exception of CCD model which experienced a variation in the mortar strength due to an increase in SDA/SDA-ESP ratio and curing age. The curing age indicated the most significant influence compared with SDA/SDA-ESP ratio for CCD and 3FD models respectively. There was an agreement between experimental data and the predicted values evident by regression values of 0.9568, 0.9696 and 0.9923, for 3FD, CCD and BBD respectively. It was also observed that mortar strength via 3FD model produced a better model compared to CCD and BBD according to the ANOVA. The ANOVA revealed that the predicted regression value (R2pred) and Regression value (R2) for 3FD model was very close compared with the other models and thus most suitable to describe the mortar strength of the SDA-ESP cement blends with R2pred =0.9091 and had R2pred = 0.8843 and R2pred =0.5050 for CCD and BBD respectively. Optimization of the strength prediction for the ternary cement blends was conducted and the optimal condition desirability of 0.997 at SDA/SDA-ESP ratio of 0.2, replacement level 6.05 wt.% and curing age of 60 days with a mortar strength of 44.02 N/mm2 respectively.
Abstract: The necessity to overcome the challenge of cumbersome and time-wasting technique of strength determination of cement blends. Several avenues are been exploited in prediction of the mortar compressive strength of ternary cement blended comprising saw dust ash (SDA) and eggshell powder (ESP). The strength gains of the cement blends were determined an...
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The Soil Slope Stability in Failure with the Use of the Random Process Based on the Kriging’s Interpolation Model
Semko Arefpanah,
Alireza Sharafi,
Fatemeh Salehi
Issue:
Volume 7, Issue 4, August 2022
Pages:
63-72
Received:
9 March 2022
Accepted:
25 March 2022
Published:
13 July 2022
DOI:
10.11648/j.jccee.20220704.13
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Abstract: The complexity of geotechnical engineerings such as slopes and Embankment is reflected not only in the change of various geotechnical parameters but also in the implicit, non-analytical, and even unverifiable nature of its functional models. Due to this feature, an example of a slope limit equilibrium model in algorithm development with an easy application for direct solution of slope engineering stability and reliability is investigated in this paper. First, the slope limit equilibrium model will be called to obtain a suitable example of the basic rock and soil parameters and the corresponding slope stability coefficient; Then, the anisotropic correlation mapping method of the Kriging model is used in ground statistics to express the value of slope performance function as a random process and process control variables are determined through samples, then Monte Carlo simulation and active learning methods together are combined. The test specimens are set according to the search rules and determine the most probable region of rupture on the slope where the slope function represented by the random process is obtained through an iterative loop, finally, the random process function is used to obtain the probability of slope rupture through simple and direct calculation in this field. Engineering analysis and calculation results show that the accuracy of this method is equivalent to the Monte Carlo simulation method, but the calculation process is simpler and has a lower and more economical calculation cost.
Abstract: The complexity of geotechnical engineerings such as slopes and Embankment is reflected not only in the change of various geotechnical parameters but also in the implicit, non-analytical, and even unverifiable nature of its functional models. Due to this feature, an example of a slope limit equilibrium model in algorithm development with an easy app...
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Used Tyre as a Resource in Concrete Production in Zambia
Theresa Bwalya,
Michael Mulenga,
Chizyuka Chizyuka
Issue:
Volume 7, Issue 4, August 2022
Pages:
73-80
Received:
14 June 2022
Accepted:
9 July 2022
Published:
20 July 2022
DOI:
10.11648/j.jccee.20220704.14
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Abstract: The construction industry needs to find cost-effective materials to enhance the properties of concrete. Cement and aggregate are the major constituents in concrete production. This has inevitably led to a continuous and increasing exploitation of natural materials to produce the constituents for concrete production. The result has been the depletion of virgin raw materials and increased effects of environmental degradation. In this research, a study was carried out on the use of recycled rubber tyres as a partial replacement for coarse aggregates in concrete production. Recycled waste tyre rubber is a promising material in the construction industry due to its reduced weight, elasticity, energy absorption, sound and heat insulating properties. Literature suggests that there is a significant loss in the strength of rubberized concrete with increasing tyre content. Further, workability and bond properties have been reported to reduce as well. Therefore, it is necessary to control this loss of strength and other parameters in concrete in the replacement process of natural aggregates. This research aimed at studying the compressive, tensile and bond properties of used tyre rubber reinforced concrete. Test results from laboratory experiments enabled determination of mechanical, physical and durability properties, as well as establishment of the extent of substitution of normal aggregates with waste rubber as aggregate in concrete. Three classes of concrete, C15, C20 and C25 were produced by substitution of selected percentages of aggregates by treated chopped waste tire rubber. The percentage replacement of coarse aggregates was 5, 15 and 25 per cent. The size of the chopped rubber aggregates varied from 20 mm to 19 mm. Slump, permeability and bulk density tests were conducted on fresh concrete mixes for both the normal and treated rubber modified concrete. Similarly, compressive strength, tensile splitting strength, bond test and durability against acid attack tests were conducted on hardened concrete. The research established that rubber modified concrete compares favourably with standard concrete, with up to 15 per cent replacement of coarse aggregate. At 15 per cent replacement, only 0.1 per cent loss of strength was established. There was noticeable reduction in properties with 25 per cent replacement. However, Rubber modified concrete performed better by gradual cracking at elevated temperatures. There is potential for rubber modified concrete products in Zambia which in turn mitigates adverse impacts resulting from over exploitation of natural aggregates and disposal of used rubber tires.
Abstract: The construction industry needs to find cost-effective materials to enhance the properties of concrete. Cement and aggregate are the major constituents in concrete production. This has inevitably led to a continuous and increasing exploitation of natural materials to produce the constituents for concrete production. The result has been the depletio...
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The Effect Study of Organic Phase Change Materials Applied to Building Exterior Walls
Issue:
Volume 7, Issue 4, August 2022
Pages:
81-85
Received:
18 June 2022
Accepted:
4 July 2022
Published:
20 July 2022
DOI:
10.11648/j.jccee.20220704.15
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Abstract: Phase change material (PCM) can change its physical state (such as solid solid, solid liquid, etc.) with the temperature difference between environment and material as the driving force within a certain temperature range, so as to realize heat storage or heat release. This heat storage characteristic makes its application in building energy conservation, such as building envelope, have a very broad prospect. Porous matrix composite phase change materials have a high latent heat of phase change. The thermal energy storage based on phase change materials can more effectively solve the problem of building energy supply and demand mismatch. In order to study the thermal insulation effect of phase change energy storage composites on buildings, organic phase change materials were prepared, and inorganic materials were used as the supporting materials of phase change materials. The thermal and mechanical properties of the composite phase change materials were measured. In the research, an experimental room was built, and the composite phase change materials were applied to the experimental room for experiments and simulation analysis. The results show that the prepared composite phase change materials have appropriate phase change temperature and large latent heat value. The phase change room can delay the time of peak temperature, reduce room temperature fluctuations, and improve living comfort. After many cold and heat cycles, the phase change temperature and latent heat value of the phase change material basically change little, which has good thermal stability and can be used for building insulation.
Abstract: Phase change material (PCM) can change its physical state (such as solid solid, solid liquid, etc.) with the temperature difference between environment and material as the driving force within a certain temperature range, so as to realize heat storage or heat release. This heat storage characteristic makes its application in building energy conserv...
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