GATE 2019 CE (CE2) – Question 49

Construction Materials · Concrete: constituents, mix design, short-term and long-term properties · 2 marks · Numerical answer

An M25 concrete specimen at stress 12.5 MPa initially strains $500\times10^{-6}$. After a long time its strain increases to $1000\times10^{-6}$. Under IS 456:2000, considering long-term effects, find effective modulus of elasticity (MPa).

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Correct answer: 12500 to 12500

Explanation

Initial modulus is $12.5/(500\times10^{-6})=25000$ MPa. Creep strain is $1000-500=500$ microstrain, so creep coefficient is 1. Effective modulus is $25000/(1+1)=$ **12500 MPa**, also stress divided by total long-term strain.