Analysis of Factors Affecting the Compressive Strength of Cement
Stabilized Crushed Stone Materials
MiaoYu
1
, Xiangguo Chang
1
and Shasha Chen
1
1
School of Highway
Chang’an University
Xi’an 710064
China
Keywords: Compressive strengthpredictionmodel database.
Abstract: The compressive strength of the cement stabilized macadam is one of the important parameters of design
and performance evaluation. But in the present study of mud stabilized macadam pavement structure
reasonable design and behavior analysis of strength did not realize the importance of parameter selection is
relatively insufficient. This study is based on the compressive strength of cement stabilized macadam
parameter selection as the research direction, by collecting both the compressive strength of the cement
stable macadam mixture, and modulus of the test data, Establishing database of strength , obtain various
parameters represent value under different reliability, analysis of curing age, different influence factors
such as cement dosage, and the compressive strength of the cement stable macadam mixture, Using the
mathematical regression method, the establishment of different curing age, under the condition of cement
dosage prediction equation, verified the established modulus of logarithm model has higher fitting precision,
can provide for pavement structure design and performance forecast value basis.
1 INTRODUCTION
Cement stabilized macadam base material is paving
the main bearing layer under the surface in the road
surface and at the grass-roots level, take on surface
transfer driving vertical load, and the load evenly
dispersed in the roadbed. Affected by various factors
such as construction technology and construction
environment, the influence of the easy occurrence
crack in cement stabilized base construction process,
segregation, partial loose, strength, smoothness and
other defects, which affect the quality of pavement,
caused the road all kinds of diseases.
In this study, the correlation between factors
such as cement dosage, curing age and compressive
strength was studied in this study. By comparing the
compressive strength under different conditions, the
strength prediction model was studied, and the
analysis intensity was influenced by different factors.
The values of compressive strength data are selected,
which can be used as reference for experiments .
2 DATA ANALYSIS OF
COMPRESSIVE STRENGTH TEXT
The compressive strength of cement stabilized
gravel is affected by many factors, and the data
distribution is analyzed from different influencing
factors.
(a) Curing age influence diagram
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7
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Compress ive stren gth( MPa)
Cement co ntant(%)
90%
95%
97%
对照组
(b) Cement dosage influence diagram
Fig.1 Cement stabilized gravel unconfined aging
It can be seen from figure1 (a) that, from the
perspective of the curing age, the compressive
strength of the cement stabilized gravel is at 7d, the
data volume is 400 and 28 days, the data volume is
over 600, and the time of 90 days is 400. According
to the figure1 (b) from the cement dosage, the data
of the cement stabilized gravel is mainly
concentrated in 3%, 3.5%,4%,4.5%, and 5% of the
total amount, which is over 80%.
3 THE DATA OF COMPRESSIVE
STRENGTH IS DETERMINED
BY THE VALUE
3.1 Degree of Reliability
Influenced by many factors, the pavement material
parameters have a large variability, which has a
great influence on the performance and service life
of the road surface. At present, the pavement
structure design of the reliability of the generally
accepted the range of 80% to 99%, 90%, 95% and
97% this article selects three values of high
reliability, in order to get high credible degree of
intensity values.
3.2 Selection of Representative Values
Reliability design method is actually a probability
analysis method, based on the curve of the high level
of literature, comparing the reliability condition, and
the trend of cement dose intensity values along with
age more in line with the general rules, thus choose a
reliability represent value as a representative of the
final value. To static pressure molding condition, the
skeleton dense type stable macadam mixture, cement
dosage 4.5% when change with ages and ages for 90
d change with cement dosage of compressive
strength, for example, under the assurance rate 97%,
the compressive strength of the cement stable
macadam mixture, along with the change of age
trend is more in line with the general rules, namely
with the increase of age, and in the early days (0 ~ 7
d) mixture strength is growing rapidly, medium term
(7 ~ 28 d) increase trend becomes flat, the late (28 ~
180 d) more gently. In the same way, the
compressive strength of cement stabilized crushed
stone under the guarantee rate also conforms to the
general rule, that is, the relationship between
strength and dose is roughly a linear relationship.
Therefore, under the condition of static pressure
forming, the compressive strength of the solid
cement stabilized gravel mixture is selected as the
final representative value with the value of 97%
guarantee rate. If the representative value trend of
the three guarantee rates is consistent with the
general rule, the representative value of the 95%
guarantee rate is selected as the final value.
4 THE INFLUENCE FACTORS OF
UNCONFINED COMPRESSIVE
STRENGTH
Select the compressive performance of cement
stabilized macadam mixture degree higher curing
ages, cement dosage, forming method and the
aggregate gradation type four aspects, such as
factors, through strength data contrast, analysis of
the factors under the tendency of the compressive
strength of the mixture.
4.1 Curing Age
In order to study the change of unconfined
compressive strength with age in different cement
doses the change curve of the value of compressive
strength was plotted with the age.
(a) The static pressure molding GM mixture
0 20 40 60 80 1 00 12 0 140 160 18 0
0
100
200
300
400
500
600
700
Data volume
Aging(d)
0 28 56 84 1 12 140 16 8 1 96
3
4
5
6
7
C omp r e ss i ve st r en gt h ( M Pa)
Aging (% )
3%
4%
4.5%
5%
6.00%
(b) The static pressure molding XM mixture
Fig.2 Cement stabilized gravel unconfined compressive
strength and the ages
The figure 2 shows that the cement stabilized
gravel unconfined compressive strength along with
the growth of the age, is nonlinear, according to the
change trend can be divided into three stages: when
age in 0 ~ 28 days, strength increase, the biggest can
reach 25%; At the age of 28~90 days, the strength
growth rate starts to decrease by about 2%; When
the age is greater than 90 days, the strength growth
curve flattens out and reaches the ultimate strength
of the cement stabilized gravel.
According to the practical engineering
experience, the cement macadam mixture when
designing age 90 d has basically completed the
intensity of the development, for comparison, this
paper enumerates the 4% dosage of cement mixture
unconfined compressive strength represents the
values, are shown in table 1
Table1 unconfined compressive strength of the
relationship with the age
compressive
strength/MPa
7d 28d 90d 180d
pressure
shaping GM
3.56 4.34 4.92 5.24
pressure
shaping XM
3.34 4.15 4.75 4.87
compressive
strength/MPa
7d/180d 28d/180d 90d/180d
pressure
shaping GM
68% 83% 95%
pressure
shaping XM
68% 85% 98%
The table 1 shows that when the 7 d of the
cement stable macadam mixture, the unconfined
compressive strength of about 60% of the nearly
180d, 28d of the unconfined compressive strength
has reached more than 80%, 90 d / 180 d unconfined
compressive strength ratio has been close to 90%,
and the general law of the experiment.
4.2 Cement Content
Cement dosage of the cement stabilized gravel
unconfined compressive strength and one of the
factors under the condition of different age, the
cement stabilized gravel unconfined compressive
strength with the change of cement dosage, as shown
in figure 2.
(a) The static pressure molding GM mixture
(b) The static pressure molding XM mixture
Fig.3 Cement stabilized gravel unconfined compressive
strength and cement dose relationship graph
Can be seen from figure 2, the same situation in
other conditions, cement stable macadam mixture
unconfined compressive strength increase with the
increase of dosage of cement, and the cement dosage
range, usually between intensity and dose of
approximate linear growth. Increase the dosage of
cement is helpful to improve the compressive
strength, the reason is that the increase of cement
dosage, can make the increase in the number of
cement hydration reaction of cement, and thus
enhanced the cohesive force of the mixture, thus
0 20 40 60 80 1 00 12 0 14 0 16 0 18 0 20 0
3
4
5
6
7
Compressi ve strength( MPa)
Aging (d)
3%
4%
4.5%
5%
6%
3.03.54.04.55.05.56.0
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
Compressive strength (MPa)
Ceme nt co nta nt ( %)
7d
28d
90d
180 d
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C o mpr ess ive s tr en gt h( MP a)
Cement contant(%)
7d
28d
90d
180d
improve the compressive strength. Consistent with
existing research results.
5. CONCLUSIONS
Based on the analysis of the influence factors of the
unconfined compressive strength of cement
stabilized gravel mixture, the following conclusions
are drawn:
(1) Combining with analysis and outlier data
screening, classification, sorting out the method of
calculating the strength of the representative values
under different reliability, and analyze the influence
of different influence factors on the representative
value degree, the analysis shows that the factors
affecting the strength of cement stabilized macadam
mixture are in line with the general law of
experiment, the influence of selecting typical
representative value.
(2) Analyze the influence of different influencing
factors on the index of cement stabilized macadam
mixture, and it can be concluded that the increase of
cement stabilized gravel (before 28d) is large; At the
same time, the strength increases with the increase
of cement dosage. According to the specification,
the representative value has certain accuracy and
representativeness.
(3) Using different models to predict the strength
of cement stabilized macadam mixture and the
strength of the mixture and cement dosage and
curing age the relationship between the change of
the fitting, determine the has higher fitting precision
of the cement stable macadam mixture strength
prediction equation, has high reliability verification,
for the strength of the cement stable macadam
mixture parameter selection for reference.
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