Experimental study on creep and shrinkage behavior of high strength concrete for application in high rise buildings
By: Ojha, P. N
.
Contributor(s): Singh, Brijesh.
Publisher: Thane ACC LTD 2021Edition: Vol.95(2), Feb.Description: 30-42p.Subject(s): Civil EngineeringOnline resources: Click here
In:
Indian Concrete JournalSummary: A concrete structure when subjected to sustained load presents progressive strain over time, which is associated with the creep phenomenon. An experimental study was conducted to determine the time induced creep strain of high strength concrete using creep rig of capacity 2000 kN. Creep strains are measured at regular time intervals on concrete designed with water to cementitious ratio of 0.47 and 0.20 wherein fly ash and silica fume were also used. In the current study, the experimentally measured values of creep are presented for concrete strength of about 45 MPa and 100 MPa. The experimentally obtained creep and shrinkage strain values are compared with B-3 Model, International Federation for Structural Concrete (FIB) model code 2010 and B4 model. The paper also presents the comparison of creep coefficients obtained using the above mentioned models with the values currently existing in Indian Standard IS: 456 (2000) and highlights the needs for the revision in creep coefficient in Indian Standard. The creep coefficients determined using B3 and B4 model are over estimating the values in case of high grade concrete. The creep coefficients determined using FIB model code 2010 are closer to IS: 456 (2000) values. The primary reason for over estimation of creep in high strength concrete using B3 and B4 model can be attributed to chemical volume reduction and self-desiccation along with decrease in pore humidity. The complications arise in creep prediction while using B3 and B4 model due to attenuating effects of diverse admixtures and reactive additives present in high strength concrete. In FIB model code 2010, basic creep concept has been used. Wherein, basic creep has been modelled using a logarithm function, which is infinite ongoing deformation while drying creep approaches a finite value. The creep given by FIB model code 2010 is similar to shrinkage modelling and this is one of the key factors contributing to accurate estimation of delayed deformations in high strength concrete. In the case of high strength concrete, IS: 456 (2000) creep coefficients will not hold good and needs to be revised. The FIB model code 2010 empirical equations can be adopted for the revision of IS: 456 (2000) which gives reasonably closer values to the experimental creep co-efficient compared up to 180 days of loading.
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Articles Abstract Database
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School of Engineering & Technology (PG) Archieval Section | Not for loan | 2021-2021977 |
A concrete structure when subjected to sustained load presents progressive strain over time, which is associated with the creep phenomenon. An experimental study was conducted to determine the time induced creep strain of high strength concrete using creep rig of capacity 2000 kN. Creep strains are measured at regular time intervals on concrete designed with water to cementitious ratio of 0.47 and 0.20 wherein fly ash and silica fume were also used. In the current study, the experimentally measured values of creep are presented for concrete strength of about 45 MPa and 100 MPa. The experimentally obtained creep and shrinkage strain values are compared with B-3 Model, International Federation for Structural Concrete (FIB) model code 2010 and B4 model. The paper also presents the comparison of creep coefficients obtained using the above mentioned models with the values currently existing in Indian Standard IS: 456 (2000) and highlights the needs for the revision in creep coefficient in Indian Standard. The creep coefficients determined using B3 and B4 model are over estimating the values in case of high grade concrete. The creep coefficients determined using FIB model code 2010 are closer to IS: 456 (2000) values. The primary reason for over estimation of creep in high strength concrete using B3 and B4 model can be attributed to chemical volume reduction and self-desiccation along with decrease in pore humidity. The complications arise in creep prediction while using B3 and B4 model due to attenuating effects of diverse admixtures and reactive additives present in high strength concrete. In FIB model code 2010, basic creep concept has been used. Wherein, basic creep has been modelled using a logarithm function, which is infinite ongoing deformation while drying creep approaches a finite value. The creep given by FIB model code 2010 is similar to shrinkage modelling and this is one of the key factors contributing to accurate estimation of delayed deformations in high strength concrete. In the case of high strength concrete, IS: 456 (2000) creep coefficients will not hold good and needs to be revised. The FIB model code 2010 empirical equations can be adopted for the revision of IS: 456 (2000) which gives reasonably closer values to the experimental creep co-efficient compared up to 180 days of loading.
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