Method for predicting rheological parameters of fresh concrete through slump test

Abstract

The invention discloses a method for predicting the rheological parameters of fresh concrete through a slump test. The method comprises the following steps: (1) placing a base plate on a horizontal surface; (2) fixing a parallel-light-source flat plate and a graduated flat plate on two opposite sides of the base plate; (3) placing a slump cone at the center of the base plate and allowing the axisof the slump cone to be superposed with the center of the base plate; (4) turning on a parallel lattice source and cameras; (5) pouring fresh concrete into the slump cone; (6) separating two halves ofthe slump cone to two sides at the same time so as to allow the concrete to begin to slump; (7) recording the changes of the height and radius of the concrete with time by using the cameras, and thenreading the values of slump height and radius at each time in subframes; and (8) picking out points where a radial change rate is more than 5 times the change rate of height, substituting corresponding height, radius and time values to obtain a curve, and then subjecting the curve to fitting to obtain a straight line so as to calculate an intercept and a slope, wherein the intercept is yield stress and the slope is plastic viscosity. The method of the invention simplifies the testing process of rheological parameters and reduces testing cost.

Description

Technical field [0001] The invention relates to the field of concrete parameter measurement, in particular to a method for predicting rheological parameters of fresh concrete through a slump test process. Background technique [0002] The rheological parameters of fresh concrete are important parameters for judging the performance of fresh concrete. In order to more intuitively and accurately measure the rheological properties of fresh concrete and study the flow behavior of fresh concrete, scholars from various countries have developed a variety of rheometers with different geometric shapes, different configurations and different applicable conditions in the past 20 years. [0003] Rheometers can measure the rheological parameters of fresh concrete more accurately, but most of them are not portable enough and bulky. It is difficult to carry out tests on the construction site. Rheometers are generally costly and complicated to operate, and require high test personnel. This reduces...

AI Technical Summary

Problems solved by technology

[0003] Rheometers can measure the rheological parameters of fresh concrete more accurately, but most of them are not portable enough and heavy, making it difficult to carry out testing on the construction site. Rheometers are generally expensive and complicated to operate, requiring high requirements for testers and increasing Overcame the difficulty of using rheometer in engineering site

On the other hand, the rheological properties of concrete are affected by many factors such as mix ratio, temperature, humidity, mixing process and time. If it is transported to the construction site after being measured at the mixing station, the rheological parameters of freshly mixed concrete will change. Great difficulties for concrete quality control

[0004] The slump test is a commonly used basic test on the construction site. It is easy to operate, flexible and portable, and has low requirements on the external environment. It is a relatively mature and effective method for the determination of the workability of fresh concrete. With the extensive use of admixtures, simple slump or expansion tests cannot fully reflect the performance of concrete. It is necessary to measure the rheological parameters of concrete to quantitatively reflect the performance of freshly mixed concrete.

Images