ZHENG Nanxiang BI Jiefu ZHANG Feilong Changan University China July 2017 outlines BACKGROUND 1 MATERIALS AND EXPERIMENTS 2 RESULTS 3 SUMMARY 4 LOGO Background China has built over 130 ID: 627157
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Slide1
Study on the Application of Vibration Mixing for Cement Stabilized Crushed Stone
ZHENG Nanxiang BI Jiefu ZHANG FeilongChang’an UniversityChinaJuly 2017Slide2
outlines
BACKGROUND
1
MATERIALS AND EXPERIMENTS
2
RESULTS
3
SUMMARY
4Slide3
LOGO
BackgroundChina has built over 130，000 Km freeway. The most common damage in China is reflection crack.Slide4
LOGO
Background
18-26cm asphalt surface layer
32-40cm base, cement stabilized martials
16-20cm subbase, gravel
Base.Slide5
www.themegallery.com
LOGOBackground
Need enough compressive strength to resistant the load
Can’ t be too low
Cement
Content
Too much cement may cause the shrinkage cracks
Can’t be too highSlide6
LOGO
Background
Challenge
：
Less cement
，
more strength
Point of penetration
：
Cement will clot when mixing the cement stabilized materials
Solution
：
Improve the uniformity of cement distribution
Method
：
Vibration mixingSlide7
LOGO
BackgroundFull-size vibration mixing equipmentSlide8
LOGO
Materials and experiments
Materials
：
Ordinary Portland cement C32.5 was used in the experiments. Its technical properties are shown in Table 1.
No.
Test
Results
1
Water requirement for normal consistency
（
%
）
26.4
2
Setting time
（
min
）
initial set
254
final set
376
3
Flexural strength
（
MPa
）
3 days
5.2
28 days
7.4
Compressive strength
（
MPa
）
3 days
20.4
28 days
34.2
Table 1. Technical indices of cement used in the experiments.Slide9
LOGO
Materials and experiments
Materials
：
Limestone was used as fine and coarse aggregates. Its crushing strength value is 16.04%. The density and gradation of the limestone used is shown in Tables 2, 3 and 4.
Size fraction
（
mm
）
Average relative density
Average water absorption
（
%
）
Apparent
Surface dry
Bulk density
19-26.5
2.765
2.723
2.700
0.877
9.5-19
2.746
2.718
2.702
0.601
4.75-9.5
2.702
2.572
2.496
3.066
Table 2. Density of the coarse limestone aggregate.Slide10
LOGO
Materials and experiments
Size fraction
（
mm
）
Average relative density
Relative
Absolute (g/cm
-3
)
2.36-4.75
2.613 2.609
0.6-2.362.788
2.784
0.075-0.6
2.808
2.803 < 0.075
2.8132.806
Table 3. Density of the fine aggregate
Type
Percentage passing
（
%）
31.5mm
19mm
9.5mm
4.75mm
2.36mm
0.6mm
0.075mm
Envelope
100
90-100
60-80
29-49
15-32
6-20
0-5
Target value
100
95
70
39
23.5
13
2.5
Table 4. Gradation of crushed limestone aggregateSlide11
LOGO
Materials and experimentsExperimentsThe optimum water content and maximum dry density were shown in table 5.
Cement content
（
%
）
Optimum water content
（
%
）
Maximum dry density
（
g/cm3）
24.20
2.392
3
4.312.410
4
4.56
2.412
54.77
2.430
Table 5. The optimum water content and maximum dry density.Slide12
LOGO
Materials and experimentsPreparation of the specimensCement contents
：
2%
，
3%
，
4%
，5%
Mixing method
：vibration mixing and normal mixingVibration frequency：
40HzMixing time：
20sGeometry and Size：150mm diameter × 150mm height cylindrical and 100mm × 100mm × 400mm Beam
Compaction method：static pressure compactionCure environment
：20
℃± 2 ℃
and humidity >95%Age：
7days，28days，60days
， 90daysSlide13
LOGO
Materials and experiments
Dial IndicatorSlide14
LOGO
Materials and experimentsTemperature shrinkage coefficient test
Step1.Immersed in water for 24h
Step2.Dehydration at 105
℃
last 12h
Step3.Temperature control
：
start at 40
℃，reduce rate 10
℃/30min ，keep every temperature for 3hours
，minimum temperature at -20℃
Step4.Record the deformation every 2 minutes Slide15
LOGO
ResultsNormal mixing unconfined compressive strength test results
Cement content
（
%
）
Test item
Age
（
d
）
7
28
60
90
2
（
MPa）
2.713.18
3.52
3.59
CV（
%）14.98
12.8212.94
11.53
（
MPa
）
2.04
2.67
2.95
3.02
3
（
MPa
）
3.73
4.64
5.29
5.44
C
V
（
%
）
10.33
9.35
11.71
10.7
（
MPa
）
3.09
3.92
4.44
4.58
4
（
MPa
）
4.63
6.06
6.93
7.49
C
V
（
%
）
10.55
11.2
11.28
11.27
（
MPa
）
3.83
4.94
5.65
6.10
5
（
MPa
）
5.55
7.21
8.11
8.28
C
V
（
%
）
10.30
12.33
11.45
10.48
（
MPa
）
4.61
5.98
6.72
6.85
Cement content
（
%
）
Test item
Age
（
d
）
7
28
60
90
2
2.71
3.18
3.52
3.59
C
V
（
%
）
14.98
12.82
12.94
11.53
2.04
2.67
2.95
3.02
3
3.73
4.64
5.29
5.44
C
V
（
%
）
10.33
9.35
11.71
10.7
3.09
3.92
4.44
4.58
4
4.63
6.06
6.93
7.49
C
V
（
%
）
10.55
11.2
11.28
11.27
3.83
4.94
5.65
6.10
5
5.55
7.21
8.11
8.28
C
V
（
%
）
10.30
12.33
11.45
10.48
4.61
5.98
6.72
6.85Slide16
LOGO
ResultsVibration mixing unconfined compressive strength test results
Cement content
（
%
）
Test item
Age
（
d
）
7
28
60
90
2
（
MPa）
3.073.59
3.88
3.96
CV（%）
11.44
10.399.82
10.78
（
MPa
）
2.44
2.97
3.27
3.41
3
（
MPa
）
4.28
5.33
6.04
6.17
CV
（
%
）
11.09
8.92
9.73
9.74
（
MPa
）
3.50
4.55
5.08
5.18
4
（
MPa
）
4.78
6.96
7.90
8.09
CV
（
%
）
9.73
11.21
10.20
9.85
（
MPa
）
4.43
5.68
6.32
6.46
5
（
MPa
）
5.83
8.28
9.26
9.47
CV
（
%
）
9.42
10.33
9.30
9.38
（
MPa
）
5.34
6.87
7.69
7.85
Cement content
（
%
）
Test item
Age
（
d
）
7
28
60
90
2
3.07
3.59
3.88
3.96
CV
（
%
）
11.44
10.39
9.82
10.78
2.44
2.97
3.27
3.41
3
4.28
5.33
6.04
6.17
CV
（
%
）
11.09
8.92
9.73
9.74
3.50
4.55
5.08
5.18
4
4.78
6.96
7.90
8.09
CV
（
%
）
9.73
11.21
10.20
9.85
4.43
5.68
6.32
6.46
5
5.83
8.28
9.26
9.47
CV
（
%
）
9.42
10.33
9.30
9.38
5.34
6.87
7.69
7.85Slide17
LOGO
ResultsThe average strain of the specimens.Slide18
LOGO
ResultsThe average shrinkage coefficient of the specimens.
shrinkage coefficient
Slide19
LOGO
ResultsAverage temperature shrinkage coefficient for different temperature intervals..
shrinkage coefficient
Slide20
LOGO
Summary
shrinkage coefficient
1.The vibration mixing can reduce the cement content and enhance the compressive strength, reduce the likelihood of severe cracking.
2. The vibration mixing method can reduce the drying shrinkage.
3.The vibration mixing method can reduce the temperature shrinkage slightly.Slide21
Thank You !
Presentor Bi Jiefu
Chang’an
university
E-mail:Jeff_bi@qq.com