T05362020Test method for lateral expansion of cement concrete mixtures

1Purpose, scope of application, and reference standards

This method specifies the test method for lateral expansion of cement concrete mixtures.

This method is applicable to a slump of10-80mmCement concrete mixtures and other materials using this method

2Instruments and materials

21Lateral expansion test chamber:for550mm×30m×300mmStainless steel square box with bottom and no cover,The steel plates on both sides can be pulled out or rotated to open,The test chamber is shown in the figureT05361shown

imageT05361Lateral expansion test chamber(unit of measurement:mm)

22High frequency vibrating rod:The frequency of the vibrating rod is200H,amplitude02mm,Vibration power5kw,diameter60mmwith

23steel ruler:Range not less than50m,The division value is1mm

24other:4A table tennis ball, a level ruler, a trowel, a shovel, etc

3Experimental steps

31Should be pressedT0521The regulations,Mixing and sampling of cement concrete

32Flatten the box by adjusting the cushion block and level ruler,Close the side door,The side door of the box and the bottom of the box shall not be greater than5mmThe gap. Mix with a small amount of concrete4Place ping pong balls evenly spaced at the bottom of the box,The distance between the ping pong ball and the side wall of the box is not less than50mmRotate the positioning plate to the outside of the box,Mix the well mixed concrete mixture,Load into the test chamber in two layers,The first layer is the box body12左右,Use a pestle to insert and compact in a spiral shape from the side wall of the box towards the center50down

3.3Insert the high-frequency vibrating rod vertically into the box,Distance from box wall panel100m+5mmwithin the scope of,Spread the second layer of concrete mixture all over the box,Use a pestle to insert and compact in a spiral shape from the side wall of the box towards the center50down,Flatten the surface again.

34Activate the high-frequency vibration end rod,And start timing,vibration30The high-frequency vibrating rod should be slowly lifted out,35sTurn off the vibration switch when needed,The high-frequency vibrating rod should be extracted from the box,And record the time when the ping pong ball floats to the top of the cement concrete mixturesAccurate to1s

35After vibration is completed,Pick up the ping pong ball,Fill the holes left by the vibrating rod with concrete mixture,And use a trowel to level the top surface of the concrete mixture inside the box,The maximum height difference is not greater than10mmMeasure the distance between the surface of the mixture and the top of the box,measurement5Calculate the height of the mixture inside the box,The maximum difference in height shall not exceed10mm,And take its average valueH1To constrain the pre vibration compaction height,Accurate to1mm,Use a steel ruler with equal spacing(The spacing should be30-60mm),measure5Horizontal width at the location,Take the average value as the constraint widthD,.

36Slowly pull the front and rear sliding doors away,The entire extraction process is not less than15s,Severe deformation of concrete caused by rapid loosening should be avoided. standing3minafter,Measure with a steel ruler if the distance between the two ends is greater than50mmVariable deformation of the mixture within the range(imageT05362),Measure the width of the mixed material surface,measurement5time,Take the average value as the width after losing constraintsD2And measure the height of the mixture,measurement5place,Take the average value as the height after losing constraintsH250Measurement Area MapT05362Schematic diagram of lateral expansion measurement area(unit of measurement:mm)

37After the experiment is completed,Clean the concrete inside the test chamber,And clean the test chamber and all test tools

4Result Calculation

41height variation,According to the formula(T0536-1)calculateAHHHT0536-1)in the formula:△HChange in height direction(mmH1Arithmetic mean of the height of the compacted mixture under constraint(mm),Accurate to0lmH2The arithmetic mean of the height of the compacted mixture after losing constraints(mm),Accurate tooImmThe calculation results are accurate to1mm

42lateral expansion,According to the formula(T05362)calculate

△D=D2-D(T05362in the formula:△D—Expansion in the width direction(mm)D-The arithmetic mean of the width of the compacted material under one constraint(m),Accurate to01mmD2The arithmetic mean of the width of the compacted mixture after losing its constraints(mm),Accurate to01mm

5Test Report

(1)The test report should include the following contents

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

(3)Variety, specifications, and place of origin of raw materials

(4)Cement concrete mix ratio to be tested

(5)Name, model and number of the instrument and equipment

(6)Environmental temperature and humidity

(7)Lateral expansion of concrete compositeMTheAD

(8)Other content to be explained.

provisions explanation

In cement concrete pavement towing work,Sliding formwork has become the mainstream construction method,Sliding mode tools have the characteristic of mobile forming,After dropping the wrong machine,The directional template slides down accordingly,The relationship between the directional expansion of this concrete and its standing model after picking is strictly prohibited. this method,To simulate the corresponding construction characteristics of sliding construction using cement concrete and reverse expansion test face cat. Using the deformation width of the concrete on both sides of the test box as the pricing indicator for the backward expansion of cement concrete,Adequate compaction should be carried out on the mixing during the experiment,And after the lateral mold frame is extracted,After stabilizing the concrete form, it should be maintained,Measure the width of the two inverted deformations again