Extreme Early Age Strength Prediction Of Concrete Based On Maturity Method

In order to speed up the construction progress and increase the turnover rate of the formwork,it is necessary to accurately monitor the development of concrete strength at the very early age during the construction.The maturity method is a simple and efficient strength prediction method,but there is still a lack of research on whether it is applicable to very early age concrete.This paper uses the maturity method to study the strength of concrete at very early ages.The article first studied the development law of concrete strength at very early age;The applicability test of maturity at the very early age verifies whether the maturity rule is applicable at the very early age of concrete;Establishing a concrete strength prediction model at the very early age through laboratory tests,and verifing the prediction effect of the established strength prediction model through the prediction accuracy verification test;Finally,through the constant temperature curing test of cement paste,the mechanism of the maturity method to predict the strength of concrete is discussed,and the correlation between the strength and maturity is analyzed from the microscopic level using X-ray diffraction analysis technology.Research indicates:(1)The strength development of concrete in the very early age shows a law of linear growth first and then logarithmic function growth.In the very early age,the higher the curing temperature of concrete,the faster the hydration rate,the higher the early strength,and the later strength will generally decrease.The extremely high curing temperature in the very early age is not conducive to the development of later strength.(2)The maturity rule is completely applicable to the very early age concrete with age less than 3d.Using the maturity method to predict the strength of concrete at very early age requires temperature correction to the maturity formula.For concretes with different material composition and strength grades,the relationship between the maturity and strength of the very early age can be expressed by an exponential function relationship,Using this relationship to predict the strength of concrete at very early ages,the relative prediction error can be controlled within 8%.(3)Maturity and hydration are conceptually equivalent,and the relationship between the two and the strength is not affected by the temperature history of concrete.When the maturity of the cement stone with the same material composition and the same mixing ratio is equal,the cement stone has roughly the same amount of hydration products generated inside,and the corresponding strength is roughly equal and has nothing to do with the temperature history.The maturity rule is suitable for each age Concrete.