Evaluation method for creep property of LUHPC

An evaluation method for creep property of LUHPC, including the following steps:

• S1, testing compressive strength, elastic modulus, environmental temperature and humidity, and creep deformation variables of LUHPC prism samples;
• S2, based on test data obtained in the step S1, calculating first creep coefficients of LUHPC at different ages and different steel fiber contents, and establishing a primary LUHPC creep model;
• S3, performing nonlinear regression analysis on the primary LUHPC creep model and fitting it by using a least squares method to establish a secondary LUHPC creep model regarding the compressive strength and the steel fiber content;
• S4, calculating a second creep coefficient based on the secondary LUHPC creep model, and evaluating a creep property of lightweight ultra high performance concrete by the second creep coefficient;
• in the step S2, the primary LUHPC creep model is established based on CEB-FIP (1990) creep model, and its expression is as follows:
• φ(t,t0)=φ0kββc(t−t0)kα;
• in the above equation, φ(t, t0) represents the first creep coefficient at loading age t0 and calculation age t;
• φ0 represents a nominal creep coefficient;
• βc(t−t0) represents a development function of creep over time after loading;
• kα is an influence coefficient of concrete compressive strength, and kβ is an influence coefficient of steel fiber.