scholarly journals Towards green concrete: Response of oyster shell powder-cement concrete to splitting tensile load

2020 ◽  
Vol 39 (2) ◽  
pp. 363-368
Author(s):  
O.A. Ubachukwu ◽  
F.O. Okafor
Keyword(s):  
Tensile Strength ◽  
Tensile Load ◽  
Oyster Shell ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Cement Concrete ◽  
Green Concrete ◽  
Curing Period ◽  
Oyster Shell Powder ◽  
Shell Powder

The menacing effects of global warming, rising cost of cement, high energy requirements for the production of cement, and the mitigation of environmental pollution have led researchers towards using locally available materials to partially replace cement in concrete or mortar. The concrete produced from such locally available material is called Green Concrete. Few researches have been reported on the usage of Oyster Shell Powder (OSP) to partially replace the Ordinary Portland Cement (OPC). However, none of those reports has reflected the response of such Green Concrete made with Oyster Shell Powder to Splitting Tensile load. In this research, OPC is partially replaced with OSP at the rate of 0%, 5%, 10%, 15%, 20% and 25% in concrete. A total of 72 number of cylindrical metal moulds of 150mm diameter and 300mm height are used to cast the concrete, demoded after 24 hours and cured for 3, 7, 14 and 28 days with three replicates for each curing age and each replacement percentage. The  properties of fresh and hardened concrete were quantified. The results show that the increase of OSP from 0% up to 25% delays the initial and final setting times of cement paste by 25mins and 40mins respectively. It also improves workability by an additional slump of 19mm. In addition, the Splitting Tensile Strength decreased from 1.706N/mm2 for 0% replacement to 1.011N/mm2 for 25% replacement after a three-day curing period, as well as from 2.076.N/mm2 for 0% to 1.388N/mm2 for 25% replacement, after a 28-day curing period. In as much as the Splitting Tensile Strength of concrete is known to be very low relative to its compressive strength; this study has reflected the extent of vulnerability of OSP-Cement concrete to tensile cracking and stress due to loads. Hence, this will result in safer design and loading of such concrete. Keywords: Concrete, Cement, Oyster Shell Powder, Splitting Tensile Strength, Partial Replacement.

Effect of Oyster Shell Powder Loading on the Mechanical and Thermal Properties of Natural Rubber/Oyster Shell Composites

2017 ◽  
Vol 25 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Lefan Li ◽  
Zongqiang Zeng ◽  
Zhifen Wang ◽  
Zheng Peng ◽  
Xiaodong She ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Coupling Agent ◽  
Oyster Shell ◽  
Absorption Bands ◽  
Tear Strength ◽  
Oyster Shell Powder ◽  
Shell Powder

The oyster shell powder/natural rubber composites were successfully prepared by blending the modified oyster shell powder with natural rubber (NR). The oyster shell powder with a particle size of 209 nm were well distributed within the rubber matrix. The characteristic Fourier transform infrared spectroscopy (FTIR) absorption bands of both oyster shell powder and natural rubber were observed in the FTIR spectra of NR/oyster shell powder composites. The C-O absorption bands in carbonates of composites exhibit a shift from 1425 cm−1 to 1446 cm−1 which suggests the bonds formed among oyster shell powder, earth coupling agent and NR. The tensile strength and stress at 500% elongation increased with rising of the earth coupling agent. Composites with 1.5 parts per hundred rubber (phr) coupling agent achieved the highest mechanical properties, where an increase of 13.4% in tensile strength was found. The tensile strength and tear strength increased along with an increment of oyster shell powder. When the content of oyster shell powder attained 25–30 phr, the composites exhibited the best mechanical properties. In particular, the tensile strength and tear strength increased by 27.9% and 17.2% when compared with those of the control samples. Furthermore, the addition of the oyster shell powder leads to the improvement of thermal stability which is evidenced by an increase of 8 °C in the initial degradation temperature. The improvement of the mechanical properties and thermal stability of the composites have demonstrated that the oyster shell powder can be used as potential fillers for natural rubber.

The Properties of Concrete with Recycled Clay-Brick-Powder

2011 ◽  
Vol 99-100 ◽  
pp. 826-831 ◽  
Author(s):  
Li Zheng ◽  
Zhi Ge ◽  
Zhan Yong Yao ◽  
Ren Juan Sun ◽  
Jun Gui Dong
Keyword(s):  
Tensile Strength ◽  
Average Particle Size ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Orthogonal Experimental Design ◽  
Average Particle ◽  
Clay Brick ◽  
Cement Concrete ◽  
Replacement Ratio ◽  
Brick Powder

This paper studied the splitting tensile strength of concrete containing partial clay-brick-powder. Four variables, water to cementitious material ratio (W/CM), sand ratio, cement replacement ratio, and the average particle size of clay-brick-powder were determined to analyze the affected factors on the properties of the concrete. The orthogonal experimental design table L16 (45) was adopted to study the significance sequence of the variables. Total 17 type mixes, including one normal cement concrete as reference, were tested. Experiment results showed that recycled clay-brick-powder could be used as partial replacement of cement in concrete. The splitting tensile strength of samples with clay-brick-powder ranged from 2 to 4MPa.

scholarly journals Predictive Modeling of Mechanical Properties of Silica Fume-Based Green Concrete Using Artificial Intelligence Approaches: MLPNN, ANFIS, and GEP

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7531
Author(s):  
Afnan Nafees ◽  
Muhammad Faisal Javed ◽  
Sherbaz Khan ◽  
Kashif Nazir ◽  
Furqan Farooq ◽  
...  
Keyword(s):  
Machine Learning ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silica Fume ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Learning Models ◽  
Green Concrete ◽  
Machine Learning Models

Silica fume (SF) is a mineral additive that is widely used in the construction industry when producing sustainable concrete. The integration of SF in concrete as a partial replacement for cement has several evident benefits, including reduced CO2 emissions, cost-effective concrete, increased durability, and mechanical qualities. As environmental issues continue to grow, the development of predictive machine learning models is critical. Thus, this study aims to create modelling tools for estimating the compressive and cracking tensile strengths of silica fume concrete. Multilayer perceptron neural networks (MLPNN), adaptive neural fuzzy detection systems (ANFIS), and genetic programming are all used (GEP). From accessible literature data, a broad and accurate database of 283 compressive strengths and 149 split tensile strengths was created. The six most significant input parameters were cement, fine aggregate, coarse aggregate, water, superplasticizer, and silica fume. Different statistical measures were used to evaluate models, including mean absolute error, root mean square error, root mean squared log error and the coefficient of determination. Both machine learning models, MLPNN and ANFIS, produced acceptable results with high prediction accuracy. Statistical analysis revealed that the ANFIS model outperformed the MLPNN model in terms of compressive and tensile strength prediction. The GEP models outperformed all other models. The predicted values for compressive strength and splitting tensile strength for GEP models were consistent with experimental values, with an R2 value of 0.97 for compressive strength and 0.93 for splitting tensile strength. Furthermore, sensitivity tests revealed that cement and water are the determining parameters in the growth of compressive strength but have the least effect on splitting tensile strength. Cross-validation was used to avoid overfitting and to confirm the output of the generalized modelling technique. GEP develops an empirical expression for each outcome to forecast future databases’ features to promote the usage of green concrete.

The effect of oyster shell powder on the extension of the shelf life of tofu

2007 ◽  
Vol 103 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Young Soon Kim ◽  
Yang Mun Choi ◽  
Dong Ouk Noh ◽  
Seung Yong Cho ◽  
Hyung Joo Suh
Keyword(s):  
Shelf Life ◽  
Oyster Shell ◽  
Oyster Shell Powder ◽  
Shell Powder

Rendering polypropylene biocomposites antibacterial through modification with oyster shell powder

Polymer ◽  
2019 ◽  
Vol 160 ◽  
pp. 265-271 ◽  
Author(s):  
Chi-Hui Tsou ◽  
Chin-San Wu ◽  
Wei-Song Hung ◽  
Manuel Reyes De Guzman ◽  
Chen Gao ◽  
...  
Keyword(s):  
Oyster Shell ◽  
Oyster Shell Powder ◽  
Shell Powder

scholarly journals Calcined Oyster Shell Powder as an Expansive Additive in Cement Mortar

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1322 ◽  
Author(s):  
Joon Ho Seo ◽  
Sol Moi Park ◽  
Beom Joo Yang ◽  
Jeong Gook Jang
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Autogenous Shrinkage ◽  
Oyster Shell ◽  
Heat Of Hydration ◽  
Strength Development ◽  
Flow Loss ◽  
Hardened Properties ◽  
Oyster Shell Powder ◽  
Shell Powder

The present study prepared calcined oyster shell powder having chemical composition and crystal structure of calcium oxide and lime, respectively, and investigated the fresh and hardened properties of cement mortar incorporating calcined oyster shell powder as an additive. The test results indicated that the hydration of calcined oyster shell powder promoted the additional formation of Ca(OH)2 at the initial reaction stage, thereby increasing the heat of hydration. In particular, the volumetric increase of calcined oyster shell powder during hydration compensated the autogenous shrinkage of mortar at early ages, ultimately leading to a clear difference in the shrinkage values at final readings. However, an excessive incorporation of calcined oyster shell powder affected the rate of C–S–H formation in the acceleratory period of hydration, resulting in a decrease in the compressive strength development. Meanwhile, the degree of flow loss was inconsequential and rapid flow loss was not observed in the specimens with calcined oyster shell powder. Therefore, considering the fresh and hardened properties of cement mortar, the incorporation of calcined oyster shell powder of approximately 3% by weight of cement is recommended to enhance the properties of cement mortar in terms of compressive strength and autogenous shrinkage.

Fire-retardant plastic material from oyster-shell powder and recycled polyethylene

2005 ◽  
Vol 99 (4) ◽  
pp. 1583-1589 ◽  
Author(s):  
Mi Hwa Chong ◽  
Byoung Chul Chun ◽  
Yong-Chan Chung ◽  
Bong Gyoo Cho
Keyword(s):  
Plastic Material ◽  
Fire Retardant ◽  
Oyster Shell ◽  
Recycled Polyethylene ◽  
Oyster Shell Powder ◽  
Shell Powder
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