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Effect of Particle Size on Properties of Concrete with Rubber Crumbs
Issue:
Volume 10, Issue 3, May 2022
Pages:
79-87
Received:
16 May 2022
Published:
19 May 2022
DOI:
10.11648/j.ajce.20221003.11
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Abstract: The number of waste tires is increasing in recent decades. Landfilling and incineration are not only consuming the land resources, but also severely endangered the ecological environment and human health. Therefore, how to recycle waste tires effectively becomes an urgent issue. Certain researches have established that crushing waste tire into powders and adding them in concrete mixer can improve the brittleness and durability of concrete materials. In this paper, the workability, mechanical properties and durability of concrete with rubber crumbs (RCC) were studied. Fine aggregate (FA) was replaced by rubber crumbs of 6 particle sizes, the usage equaled the 10% volume of the FA. The microstructure and pore structure of RCC are analyzed by SEM and MIP. The test results revealed: (1) Due to the difference of air entrainment and absorption, rubber crumb with different particle sizes has different effects on the workability of concrete mixture; (2) The addition of rubber crumbs reduced the strength of concrete, but the relationship between strength and particle size was not monotonous. The compressive strength of RCC decreased at first, then increased with the increase of particle size; (3) The air entraining effect of rubber powder can improve the frost resistance of concrete; (4) The changes of micro morphology and pore structure led to the modification of performances of RCC.
Abstract: The number of waste tires is increasing in recent decades. Landfilling and incineration are not only consuming the land resources, but also severely endangered the ecological environment and human health. Therefore, how to recycle waste tires effectively becomes an urgent issue. Certain researches have established that crushing waste tire into powd...
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Numerical Finite Element Analysis of the Soil Mass Subjected to the Impulsive Load of a Standard Penetration Test (SPT): Assessment of Young’s Modulus of Soils
Zoa Ambassa,
Amba Jean Chills
Issue:
Volume 10, Issue 3, May 2022
Pages:
88-108
Received:
1 April 2022
Accepted:
22 April 2022
Published:
26 May 2022
DOI:
10.11648/j.ajce.20221003.12
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Abstract: In this paper, we propose a method for the direct determination of the Young's modulus of soils from the Standard Penetration Test by performing back-calculations iteratively knowing the reference sinkage which is 30 cm. We modeled the Standard Penetration Test taking into account the experimental protocol in the field and the typical Impulsive load subjected in the soils mass. Numerical simulations have been carried out using the Finite Element calculation code Cast3M in 2-D axisymmetric. For all the calculations, the Poisson's ratio was taken as equal to 0.3 for the soil and a unit weight of all the soils set at 17 kN/m3. The influence of the drilling diameter was taken into account, with two modeled pre-drilling diameters, 65 and 200 mm. From these dynamic calculations at small time steps, carried out in a semi-infinite soil mass without natural water content, it appears that the Young's modulus of the soils determined by our method, strongly depends on the number of blows at the SPT of the test depth and the diameter of the borehole. Tables, charts for practical use and a direct relationship for determining the Young's modulus of soils subjected by SPT by this method have been established and proposed in this paper funtion of the number of blows at the SPT.
Abstract: In this paper, we propose a method for the direct determination of the Young's modulus of soils from the Standard Penetration Test by performing back-calculations iteratively knowing the reference sinkage which is 30 cm. We modeled the Standard Penetration Test taking into account the experimental protocol in the field and the typical Impulsive loa...
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Finite Element Analysis of Cable-Stayed Cantilever Material Transfer Platform Under Varying Loading Conditions
Haifeng Yu,
Chun Wang,
Jinyuan Li,
Wenjun Ji,
Deqiang Yu,
Hao Wang,
Jiaqi Li
Issue:
Volume 10, Issue 3, May 2022
Pages:
109-115
Received:
31 May 2022
Published:
1 June 2022
DOI:
10.11648/j.ajce.20221003.13
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Abstract: During the construction of building structures, the transfer platform is the main passage of materials entering or departing the floor, and it is an important facility for site operation. In recent years, a large number of construction accidents have occurred due to unsafe design and unreasonable site practices of the transfer platform, and serious accidents may result in injury or death. Aiming at the decrease of construction accidents of the transfer platform, this paper studied the force characteristics of the cable-stayed cantilever material transfer platform under varying loading conditions using the finite element method. The maximum load-carrying capacity of the transfer platform was obtained, and the most unfavorable position of the material load was analyzed. The performance in service of the transfer platform under various adverse conditions such as partial load and anchorage failure was studied. The results show that when the load area is less than or equal to 0.5m×0.5m, the maximum load-carrying capacity of the transfer platform is 8kN after considering the dynamic coefficient. When the material load is located in the middle of the transfer platform, the transfer platform has a good safety margin. And when the main girder anchor bodies or wire rope anchorages are not anchored, the transfer platform cannot be used.
Abstract: During the construction of building structures, the transfer platform is the main passage of materials entering or departing the floor, and it is an important facility for site operation. In recent years, a large number of construction accidents have occurred due to unsafe design and unreasonable site practices of the transfer platform, and serious...
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Numerical Simulation on Mechanical Properties of Segmental Prefabricated Concrete T-section Beams
Jianqing Bu,
Lingpei Meng,
Zhenyu Wang,
Yucheng Zhao,
Jingchuan Xun
Issue:
Volume 10, Issue 3, May 2022
Pages:
116-124
Received:
13 June 2022
Published:
14 June 2022
DOI:
10.11648/j.ajce.20221003.14
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Abstract: At present, there are few application cases of segmental prefabricated concrete T-section beams in bridge structures, and the research on mechanical properties is still insufficient. The division of segments makes the beam body have multiple joints, and the longitudinal reinforcement cannot be arranged continuously, which results in the discontinuous local mechanical behavior of the beam body at the joint position. In this paper, 6 beams are selected, and the number of single key-joint at the joint and the shear-span ratio are used as independent variables for research. The finite element model was established by ABAQUS software to simulate the stress and deflection, and ultimate bearing capacity of the segmental precast concrete T-section joint beams under two load cases. The following conclusions can be obtained by the data processed, which can provide a reference for the optimal design of segmental prefabricated concrete T-section beams in engineering applications. The conclusions include: that the joint sections of B and C conform to the assumption of plane section. Under the two-shear-span ratio, the stress transfer of the integral beam is better than that of the segmental beam, and the single key-joint beam is superior to the double key-joints segmental beam. At the joint section, the stress transfer of the same type of beam is better with a shear-span ratio of 2.3 than with a shear-span ratio of 3.3. When the shear-to-span ratio is the same, the bending stiffness of the integral T-section beams is the largest among the three beams. The second is the single key-joint segment beam, and the last is the double key-joints segment beam. When the shear-to-span ratio is different, the deflection when the shear-span ratio is 3.3 is more significant than when the shear-span ratio is 2.3. In conclusion, the mechanical properties of the integral beam are better than those of the other two segmental beams, and the mechanical properties of the single key-joint segmental beam are relatively better than that of the double key-joints segmental beam.
Abstract: At present, there are few application cases of segmental prefabricated concrete T-section beams in bridge structures, and the research on mechanical properties is still insufficient. The division of segments makes the beam body have multiple joints, and the longitudinal reinforcement cannot be arranged continuously, which results in the discontinuo...
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The Structural Dynamic Evaluation of Wadaslintang Dam to the Earthquake Acceleration Based on Indonesian Seismic Code 2019
Dwi Astuti Wahyu Wulan Pratiwi,
Lalu Makrup,
Imam Setiawan
Issue:
Volume 10, Issue 3, May 2022
Pages:
125-134
Received:
17 May 2022
Accepted:
10 June 2022
Published:
20 June 2022
DOI:
10.11648/j.ajce.20221003.15
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Abstract: Dam evaluation needs to be carried out, to look back at the deformation of the dam structure during decades of operation. In this study, the structure of Wadaslintang dam will be evaluated based on dynamic earthquake loading on the basis of the 2019 Indonesian earthquake hazard map. Dynamic evaluation of the dam requires dynamic earthquake acceleration in the form of a acceleration time history that was developed deterministically. Based on the theory of dam or soil deformation that was formatted in the GEOSTUDIO computer program and the program used in this research with the soil and earthquake time history data, so the deformation of the Wadaslitang dam can be computed. From the computation results can be stated that the dam safe to deformation. The result of the Wadaslitang dam evaluation was the vertical and the horizontal deformation has smaller deformation than the set requirement.
Abstract: Dam evaluation needs to be carried out, to look back at the deformation of the dam structure during decades of operation. In this study, the structure of Wadaslintang dam will be evaluated based on dynamic earthquake loading on the basis of the 2019 Indonesian earthquake hazard map. Dynamic evaluation of the dam requires dynamic earthquake accelera...
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Gel-bound Colourants as a Substitute for the Sprayed Application of pH-Indicator Solution
Nico Vogler,
Jens Lehmann,
Tatjana Bohlmann,
Jens Kronemann
Issue:
Volume 10, Issue 3, May 2022
Pages:
135-144
Received:
16 May 2022
Accepted:
9 June 2022
Published:
27 June 2022
DOI:
10.11648/j.ajce.20221003.16
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Abstract: In general, pH-sensitive colorants such as phenolphthalein are applied on freshly split surfaces of building structures to determine the state of carbonation. For years, it has been known that the aerosols of phenolphthalein are suspected of being carcinogenic. Hence, more work has currently being done on alternative indicators for the use in research and the use on construction sites. Over the past years, mainly pH indicators from other research areas and natural dyes were investigated for their usability to cementitious systems. This paper presents the experimental results of using phenolphthalein solution bound in agar-agar gel. This gel-bound indicator allows the future use of the already known phenolphthalein dye without the health hazards for the user. To demonstrate the flexibility of the gel-bound colorant, different application forms of the indicator were carried out and assessed. In addition, the results obtained by the different methods were statistically evaluated to ensure validity. The accuracy of the results was confirmed by thermogravimetric analysis and IR spectroscopic studies as reference methods. It has also succeeded to demonstrate the comparability of the results achieved by the gel-bound colorant with the results of the common sprayed application method. As an additional gain in knowledge, comparative results of indicator tests, TGA analysis, and FTIR investigation are shown.
Abstract: In general, pH-sensitive colorants such as phenolphthalein are applied on freshly split surfaces of building structures to determine the state of carbonation. For years, it has been known that the aerosols of phenolphthalein are suspected of being carcinogenic. Hence, more work has currently being done on alternative indicators for the use in resea...
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