UHPC Creep and Shrinkage: Test Data and Predictive Models

Presented By: Alireza Mohebbi, Genex Systems This study investigated the creep and shrinkage behaviors of a suite of commercially available UHPC-class materials, with the goal being to characterize the behaviors then propose predictive models. The objectives of this research were as follows: a) quantify the compressive creep behavior of different UHPC-class materials; b) assess the effects of strength, maturity, and loading age on UHPC creep; c) develop data-driven models to predict ultimate creep coefficients and shrinkage strains of UHPC-class materials for different service conditions; d) compare the predictive models with measured data, AASHTO LRFD Bridge Design Specifications equations, and existing European recommendations for UHPC-class materials; e) examine the applicability of the proposed models by incorporating the material models into a prestress loss model then comparing the predictions to the behaviors of seven full-scale pretensioned UHPC girders. The creep and shrinkage data for different materials were observed to vary somewhat independently from the variables commonly engaged in predictive models, leading to model predictions that were generally indicative of the material response.