TY - JOUR

T1 - Solidification theory for concrete creep. I

T2 - Formulation

AU - Bazant, Zdenek P.

AU - Prasannan, Santosh

PY - 1989/8

Y1 - 1989/8

N2 - The paper presents a new general constitutive law for creep in which the aging due to continuing hydration of cement is taken into account in a manner that is both simpler and physically better justified than in existing theories. Micromechanical analysis of the solidification process is used to show that the aging may be modeled as a growth of the volume fraction of load-bearing solidified matter (hydrated cement), which itself is treated as nonaging and thus is describable as a nonaging viscoelastic material. The analysis shows that a history integral should be used to express the rate, rather than the total value, of the viscoelastic strain component. Material functions can be chosen in a way that yields previously established simple laws, i.e., the double power law, logarithmic law and log-double power law, as special asymptotic cases. The creep strain is obtained as a sum of aging and nonaging viscoelastic strains and an aging viscous strain (flow). Nonlinearity is introduced by modifying the current creep rate as a function of the current stress. Verification by test results and numerical application is left to Part II, which follows.

AB - The paper presents a new general constitutive law for creep in which the aging due to continuing hydration of cement is taken into account in a manner that is both simpler and physically better justified than in existing theories. Micromechanical analysis of the solidification process is used to show that the aging may be modeled as a growth of the volume fraction of load-bearing solidified matter (hydrated cement), which itself is treated as nonaging and thus is describable as a nonaging viscoelastic material. The analysis shows that a history integral should be used to express the rate, rather than the total value, of the viscoelastic strain component. Material functions can be chosen in a way that yields previously established simple laws, i.e., the double power law, logarithmic law and log-double power law, as special asymptotic cases. The creep strain is obtained as a sum of aging and nonaging viscoelastic strains and an aging viscous strain (flow). Nonlinearity is introduced by modifying the current creep rate as a function of the current stress. Verification by test results and numerical application is left to Part II, which follows.

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U2 - 10.1061/(ASCE)0733-9399(1989)115:8(1691)

DO - 10.1061/(ASCE)0733-9399(1989)115:8(1691)

M3 - Article

AN - SCOPUS:0024707702

SN - 0733-9399

VL - 115

SP - 1691

EP - 1703

JO - Journal of Engineering Mechanics

JF - Journal of Engineering Mechanics

IS - 8

ER -