To evaluate the practical application of crushed oyster shells (OS) as construction materials, an experimental study was performed based on equal materials proportion and the partial replacement of saturated-surface-dry (SSD) sand with dry oyster shell. More specifically, the long-term mechanical pr...
To evaluate the practical application of crushed oyster shells (OS) as construction materials, an experimental study was performed based on equal materials proportion and the partial replacement of saturated-surface-dry (SSD) sand with dry oyster shell. More specifically, the long-term mechanical properties and durability of concrete with OS partially substituted for fine aggregate were investigated. Test results indicate that long-term strength of concrete with 10% OS replacement is almost identical to that of normal concrete. However, the long-term strength of concrete with 20% OS replacement is appreciably lower than that of normal concrete. Therefore, higher OS substitution has the possibility of negatively influencing the concrete long-term strength increment. Elastic modulus of concrete with OS replacement decreases as the substitution mixture ratio increases. Specifically, the modulus is reduced by approximately 10-15% when OS are used for 20% of the fine aggregate. The drying shrinkage strain increases as the substitution ratio (SR) of OS is increased. In addition, the existing model code for drying shrinkage and creep does not coincide with the test results of the present study. A prediction equation for drying shrinkage has been developed. The utilization of OS as a fine aggregate in concrete has a positive effect on freezing and thawing resistance and water permeability is also considerably improved. However, OS has no apparent effect on carbonation and chemical attack of concrete. Finally, it is noted that the strength, elastic modulus, drying shrinkage, freezing and thawing resistance, and permeability are significantly affected by increased OS substitution, particularly for long-term performance, while other properties such as creep and carbonation, as well as chemical attack test results, were not substantially affected.
To evaluate the practical application of crushed oyster shells (OS) as construction materials, an experimental study was performed based on equal materials proportion and the partial replacement of saturated-surface-dry (SSD) sand with dry oyster shell. More specifically, the long-term mechanical properties and durability of concrete with OS partially substituted for fine aggregate were investigated. Test results indicate that long-term strength of concrete with 10% OS replacement is almost identical to that of normal concrete. However, the long-term strength of concrete with 20% OS replacement is appreciably lower than that of normal concrete. Therefore, higher OS substitution has the possibility of negatively influencing the concrete long-term strength increment. Elastic modulus of concrete with OS replacement decreases as the substitution mixture ratio increases. Specifically, the modulus is reduced by approximately 10-15% when OS are used for 20% of the fine aggregate. The drying shrinkage strain increases as the substitution ratio (SR) of OS is increased. In addition, the existing model code for drying shrinkage and creep does not coincide with the test results of the present study. A prediction equation for drying shrinkage has been developed. The utilization of OS as a fine aggregate in concrete has a positive effect on freezing and thawing resistance and water permeability is also considerably improved. However, OS has no apparent effect on carbonation and chemical attack of concrete. Finally, it is noted that the strength, elastic modulus, drying shrinkage, freezing and thawing resistance, and permeability are significantly affected by increased OS substitution, particularly for long-term performance, while other properties such as creep and carbonation, as well as chemical attack test results, were not substantially affected.
Cem Concr Res Yang 35 11 2175 2005 10.1016/j.cemconres.2005.03.016 Effect of oyster shell substituted for fine aggregate on concrete characteristics: part I. Fundamental properties
J Korea Concr Inst Yang 15 2 280 2003 10.4334/JKCI.2003.15.2.280 Long-term performance evaluation of concrete utilizing oyster shell in lieu of fine aggregate
ACI Committee 201. Guide to durable concrete, ACI manual of concrete practice (ACI 201R-92). American Concrete Institute; 1997. 39 pp.
Korea Concrete Institute. Standard specifications for concrete; 1999. 250 pp [in Korean].
CEB. Durable concrete structures. Thomas Telford; 1992. 112 pp.
Korea Concrete Institute and Architectural Institute of Korea. Standard for structural calculations of reinforced concrete structures; 1999. 319 pp [in Korean].
American Society for Testing and Materials. Standard test method for compressive strength of cylindrical concrete specimens. ASTM C 39-01, Philadelphia.
Neville 1997 Properties of concrete
American Society for Testing and Materials. Standard test method for static modulus of elasticity and Poisson’s ratio of concrete in compression. ASTM C 469-94, Philadelphia.
American Society for Testing and Materials. Standard test method for resistance of concrete to rapid freezing and thawing. ASTM C 666-97, Philadelphia.
American Society for Testing and Materials. Standard test method for compressive strength of hydraulic cement mortars (using 2-in. or 50-mm cube specimens). ASTM C 109-01, Philadelphia.
ACI Committee 209. Prediction of creep, shrinkage, and temperature effects in concrete structures. ACI manual of concrete practice (ACI 209R-92). American Concrete Institute; 1997.
CEB-FIP. Model code for concrete structures (MC-90). London: CEB, Thomas Telford; 1993. 112 pp.
Bazant 1982 Creep and shrinkage in concrete structures
AI-Helper
※ AI-Helper는 부적절한 답변을 할 수 있습니다.