T0533-2020Cement concrete mixtureJEnvironmental testing method

1Purpose, scope of application, and reference standards

This method specifies the cement concrete mixtureJTest method for rings

This method is suitable for evaluating the filling and passing capacity of self compacting concrete and high flow concrete.

Reference standards

Concrete slump testerJGT248

Technical Specification for Application of Self compacting Concrete(JT283)

Mixing and on-site sampling methods for cement concrete mixtures(T0521)

2Instruments and materials

2.1Jring:from16Rooted in8Steel bar composition,JThe diameter of the ring is300m,The specific dimensions of the experimental device are shown in the figureT05331As shown.

3Experimental steps

3.1Test method and steps for slump expansion of concrete,Should be pressedT0532The regulations are in place. Record the unfolding of the concrete

The maximum diameter of a circled1,And the diameter perpendicular to the maximum diameterd2The final slump expansion of the concrete mixture is the average of two diametersd,The measurement should be accurate to1mm,Result rounding up to5mm32JExpansion of circular collapse

(1)In1LLoad into an iron drum671Freshly mixed concrete,And let it stand still6O+10s

(2)Standing still in concrete6+10within the time,Wet the bottom plate and slump cone with sponge or towel,There should be no visible water on the inner wall and bottom plate of the slump cone:The base plate is placed on a solid horizontal surface,Slump simplicity“positive”Place it at the bottom edge of the center position of the base plate and200mThe scale circles overlap,JThe ring is placed outside the slump,Lower edge and300mThe scale circles overlap,During the loading process, the position of the falling bamboo remains fixed and does not move

(3)Add concrete inside the iron rod to the falling rod,Fill to full without layering at once,And no vibration or reinforcement is applied throughout the entire process

(4)Scrape off the remaining material at the top of the concrete filled in the slump cone with a spatula,Make it level with the upper edge of the slump cone,Remove excess concrete around the chassis collapse cylinder and then lift the collapse cylinder vertically and steadily(From filling the slump cone with concrete to lifting it up,The time interval shall not exceed40s),Allow the concrete to flow freely. The lifting process of the slump cone should be carried out during3~7sCompleted internally;The entire process from loading to lifting off the slump cone should be carried out continuously,and150sCompleted internally

(5)When the concrete mixture no longer diffuses or the duration of diffusion reaches50stime,Record the maximum diameter of the unfolded circle of concreteD,And the diameter perpendicular to the maximum diameterD2The final slump expansion of the concrete mixture is the average of two diametersD,The measurement should be accurate tomm,Result rounding up to5mm33Performance indicators for gap passing of self compacting concretePThe result should be the expansion of concrete slumpdandJExpansion degree of environmental periodDThe difference

34Observe the condition of the concrete after collapse,If it is found that coarse aggregates accumulate in the center or there is a significant amount of cement slurry precipitation at the edges of the concrete after final expansion,This concrete mixture has poor anti segregation properties,Should be recorded

4Test Report

The test report should include the following contents

(1)Name and execution standards of the required testing items

(2)Types, specifications, and origins of raw materials, as well as concrete mix proportions

(3)Test date and time

(4)Name, model and number of the instrument and equipment;

(5)Environmental temperature and humidity;

(6)Record the slump expansion of cement concrete mixtured1Thed2TheD1TheD2equivalent

(7)Performance indicators of cement concrete gap passing throughPvalue

(8)Other content to be explained

provisions explanation

This method refers to the "Joint Meter Code for Application of Self compacting Mixed Soil"(JGu283-2012)preparation,Evaluate the filling capacity and steel bar passing capacity of cement concrete mixtures using sub evaluation. Large flow Tao concrete refers to a composite with a slump value not less than200mmThe concrete. Generally, transportation capacity and high-efficiency or ordinary water reducing agents are used,Improve its slump and flowability with high workability,Achieve easy watering,The purpose of reducing or even eliminating the vibration molding process.