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Nghiên cứu sử dụng cốt liệu đá quartzite ở thanh sơn, phú thọ để chế tạo bê tông xi măng mặt đường tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING
UNIVERSITY OF TRANSPORT AND COMMUNICATIONS

NGO HOAI THANH

RESEARCH ON UTILIZATION OF QUARTZITE
AGGREGATE IN THANH SON, PHU THO TO PRODUCE
CEMENT CONCRETE FOR ROAD PAVEMENT

Discipline
Code
Major

: Transport Construction Engineering
: 9580205
: Automobile and urban road construction

SUMMARY OF TECHNICAL DOCTORAL THESIS

HA NOI – 2019



The study was completed at
University of Transport and Communications

Academic supervisor

Prof. Dr.Pham Duy Huu
University of Transport and Communications

Referee 1:
Referee 2:
Referee 3:

The thesis will be defended in front of the university-level
doctoral thesis judgement panel at the University of Transport
and Communications.

At…….. , dated …………………………. 2019

The thesis can be found at:
- Viet Nam National Library
- UTC Library – Information Centre


1
INTRODUCTION
1. Necessity of the research
Concrete is a material that accounts for a large proportion in most construction
works. With the advantages of easy forming, good bearing capacity, long life,
being made of local materials, in the construction industry so far, concrete has
surpassed all other materials. The demand for construction of transport works is
very large (hundreds of thousands of kilometers of national highways), but in fact,
cement concrete pavement in Viet Nam is insufficient in quantity and does not
meet the quality requirements. Whereas, many countries in the world, such as the
US, Germany, China, etc. have been very successfull in construction of road and
airport pavement [28]. Quartzite in Thanh Son, Phu Tho is a kind of high quality
aggregate, with quite large reserves of approx. over 10 million tons [2]. It is
imperative to exploit local materials to manufacture concrete so as to reduce
aggregate transportation, which normally raises the construction costs.
Moreover, there have not been so far any studies and field experiments on
cement concrete in Viet Nam, which are systematic and complete regarding the
thermal properties of concrete using quartzite, i.e. calculation and real measurement
of the thermal expansion coefficient (CTE) of cement concrete using quartzite ;
investigation into the relationship between the CTE with the age and different kinds
of aggregates.
For such reasons stated above, the research on the physio-mechanical properties
of quartzite, design of concrete composition, the thermal properties of concrete
determined by the CTE, the strength and the thermal stress of concrete utilizing
quartzite aggregate from Thanh Son, Phu Tho has met the demand of traffic works
construction for high quality and efficient cement concrete while making use of the
local materials. Thus, "Research on utilization of quartzite aggregate in Thanh
Son, Phu Tho to produce cement concrete for road pavement " is essential with
obvious scientific and practical significance.
2. Aims of the research
The research aims to complete the scientific fundamentals as well as the
practice of utilizing quartzite aggregate in Thanh Son, Phu Tho to produce cement
concrete for road pavement, which meets the technical requirements of road
construction in the north-western region. It also contributes to reasonably
exploiting the local materials for construction.
3. Scope of the research
Utilization of quartzite in Thanh Son, Phu Tho as aggregate for cement concrete
in road pavement construction; Experiments on main mechanical properties of
cement concrete using quartzite in Thanh Son, Phu Tho as required by pavement


2
design and construction. The design of cement concrete pavement using quartzite
aggregate from Thanh Son, Phu Tho uses data on the load, climate, base and
subgrade as set in Decision QĐ3230[5].
4. Research methods
- Theoretical and lab-based experimental studies are combined to determine the
physio-mechanical properties of quartzite aggregate and the characteristics of
cement concrete;
- Synthetical analysis method is also employed to clarify the aims of the research as
set in the thesis.
5. Structure of the thesis
The thesis includes the Introduction, four main chapters, the Conclusions and
Recommendations, and the Direction for further study as well as the References
and Appendices.
6. New contributions given in the thesis
+ Having studied the aggregate characteristics of quartzite from Thanh Son, Phu
Tho and affirmed that this material conforms to the current standards, as a result,
can be used in cement concrete production for road pavement;
+ By experimental planning, the author has found out regression equations
describing the relationship between the objective functions, including the
compressive strength, the bending tensile strength and the influence factor, namely
the ratio X/N. The two regression equations are:

y1  19,19 X 2  5,62
y2  X 2  2,77

 2,5  X 2  3,5
 2,5  X 2  3,5

+ The experiment results of the compressive strength, tensile strength, elastic
modulus, slump of cement concrete using quartzite aggregate can serve as good
reference in teaching, design and construction of transport works.
+ Through experiments, the author has determined distortion and the thermal
expansion coefficient of concrete using quartzite and concrete using limestone
according to the age with strain gauge SDA - 830B. In detail,
- Concrete using quartzite at Days 3, 7, 14, 28 has the thermal expansion
coefficient of 11.1925, 11.2248, 11.2200 and 11.1819 (10-6/0C ), respectively.
- Concrete using limestone at Days 3, 7, 14, 28 has the thermal expansion
coefficient of 7.4791, 7.3830, 7.3996 and 7.4132(10-6/0C ), respectively.
+ Calculations show that the expected sizes of cement concrete plates using
quartzite and limestone are 4m x 3.5m x 0.25m and 4.5m x 3.5m x 0.25m as set by
Decision QĐ3230[5] by Transport Ministry.
- In design of the same composition, the strength and the thermal stress of


3
concrete using quartzite increase concurently with those of concrete using
limestone, with the tensile strength growing by 1.1% and the maximum thermal
stress going up by 33.59%.
- Due to the above stated factors, concrete pavement using quartzite is more
likely to crack on the plate surface than concrete pavement using limestone with a
deviation rate of 5.41%.
- Cement concrete plates using quartzite should be shorter than those using
limestone. The cement concrete slabs using quartzite aggregate should be 3.8m
long.
+ Quartzite concrete meets the requirements of the strength and economic
efficiency thanks to its lower cost compared to limestone concrete.
CHAPTER 1. OVERVIEW OF CEMENT CONCRETE FOR ROAD
CONSTRUCTION AND UTILIZATION OF
QUARTZITE IN CONCRETE PRODUCTION
1.1. History of cement concrete pavement development
According to documents [26] and [28], concrete is a kind of building materials
often used in large volume and indispensable in modern construction. Due to high
requirements in harsh conditions, non-reinforced cement concrete pavement has
long been used in many countries such as the UK, the USA, Russia, Germany,
China, etc. In Viet Nam, it was first used on Hung Vuong road in 1975, then in
many other projects of National Highway 2, National Highway 18, National
Highway 1A and so on.
1.2. General overview of cement concrete
According to documents [1], [21] and [22], cement concrete is an artificial
stony material obtained after the concrete mixture solidifies. Concrete mixture
includes reasonably-selected componnents, namely cement, water, aggregates and
additives. In concrete, aggregate acts as a bearing frame to enhance the mechanical
properties of concrete while the cost of concrete production reduces.
1.3. Structure of cement concrete
1.3.1. Formation of concrete structure
1.3.2. Micro, macro and Nano structures
1.4.Regulations on properties of cement concrete used for road construction
1.4.1. Regulations on aggregates to manufacture cement concrete
1.4.2.Regulations on properties of cement concrete used for road construction
The physio-mechanical and slump parameters of cement concrete mixture are
regulated by MOT Decision No. 1951 [4].
1.5.General overview of methods of designing cement concrete composition
1.5.1. Designing cement concrete composition as per ACI 211.1.91


4
According to document [34], this method combines theories and experiments.
The basic theory is the one of absolute volume. Concrete is designed in a
completely solid state with the total volume including the individual solid volumes
of material components and the air volume. Tests of the strength and slump are
conducted. Evaluation of the experiments employs the statistical probability theory
on the basis of standard distributions.
1.5.2. Designing cement concrete composition as per Bolomey-Skramtaev
According to document [15], the composition of cement concrete is designed
as follows: Step 1 (Selecting the slump), Step 2 (Determining the amount of water),
Step 3 (Determining the ratio X/N), Step 4 (Determining the amount of cement X),
Step 5 (Determining the amount of stone D), Step 6 (Determining the amount of
sand C), Step 7 (Determining the amount of superplastic additive).
1.5.3. Using the experimental planning method to identify factors
influencing the strength of cement concrete for road construction and
calculate ratio N/X
According to document [30], the output norms used to evaluate objects are
often called objective functions. Experimental planning is employed for calculation,
based on the scientific experiment plan to select the cement concrete composition
in order to satisfy 2 objective functions: the compressive strength and the bending
tensile strength of cement concrete. By experimental planning, it is possible to find
out the regression equations describing the relationship between the objective
functions: compressive strength and bending tensile strength with influencing
factors such as ration D/C, ratio X/N, thereby, calculating ratio N/X.
1.6. Investigating the geographic, topographic and geological features of
quartzite quarry in Thanh Son, Phu Tho
The quartzite quarry is located in Thuc Luyen commune, Thanh Son district, Phu
Tho province [2].

Figure1.2. Images of quartzite quarry
1.6.1. Geographic and topographic features
1.6.2. Geological features
+ Mineral geological features
The quartzite layer lies on the slate, extending from the North to the South,
about 150-200m thick, divided into 3 seams, bottom-up distributed by seams 1,2,3.
- Seam 1: Lying on the quartz mica slate, quartzite is yellowish opaque.
- Seam 2: Lying evenly on the rock clamping between the slate and quartzite


5
schist, quartzite is pinkish gray.
- Seam 3: Lying evenly on the rock clamping between the slate and quartzite
schist, widely distributed, quartzite is yellowish greyish white.
+ Quartzite quality
Quartzite available in this area falls into two types: Weathered quartzite and
solid quartzite.
Table 1.6. Chemical composition of weathered quartzite
Type
SiO2(%)
Fe2O3 (%)
Weathered quartzite
96,90
0,28
Table 1.7. Chemical composition and physio-mechanical properties of quartzite
in different seams
Order
SiO2
A1203
Water permeability
Fire resistant
(%)
(%)
(%)
temperature
1.Seam 1
97.81
1.00
0.45
> 17300
2. Seam 2
97.23
0.77
0.54
> 17300
3. Seam 3
96.68
1.11
0.97
> 17300
1.7. Studies on quartzite and pavement cement concrete using quartzite.
1.7.1. Studies on quartzite and pavement cement concrete using quartzite
in the world.
According to document [39], quartzite is a metamorphic stone from silicon
sandstone with crystalline quartz particles bound together. Quartzite is white or
pink, purple, dark because of impurities. Quartzite is well weathered. This kind of
stone is used for the outer lining of a building, or as stone and crushed stone.
Quartzite is also found among raw materials for manufacturing fire resistant
components.
Cement concrete for pavement makes use of quartzite, an artificial stony
material obtained after the concrete mixture solidifies. Concrete mixture is
composed of cement, water, coarse quartzite aggregate and fine quartzite aggregate.
According to K. Kavitha [51], the increased construction activities have entailed
the increased demand for different materials used in concrete manufacturing,
especially river sand as fine aggregates. This study has investigated the effect of
quartzite in place of fine aggregate in Grade 30 concrete (M30). Conclusions have
been drawn as follows: Quartzite sand used to replace fine aggregate has small
density and lower weight than river sand, so the specific weight of concrete can
decrease. Quartzite sand changes color well and has smooth surface, which cannot
be observed in natural sand. Quartzite sand is a better alternative than river sand at


6
reasonable costs. Therefore, it is acceptable to replace 100% fine aggregate by
quartzite sand in construction works.
According to Simma Ravi Kiran [62], concrete is widely used in infrastructure
construction. In this study, quartzite is used as an alternative to replace coarse
aggregate and its various mechanical properties and technical properties have also
been investigated. Experimental studies are performed on cement concrete by
replacing up to 100% raw aggregates. The mixed design and test methods are in
compliance with the Indian Standards Bureau. Concrete made of quartzite gives
higher compressive strength than conventional concrete.
According to Mark Adom [53] from Ghana, quartzite is kind of rock forming
the mountains, locally called Akwapim range running across the eastern region and
extending into the Volta region. This rocky range forms part of the regional
geology called the Togo Series. Quartzite is quartz-rich stone. The stone has glassy
color and its colors can vary from white to black, cream, pink, red and gray.
Utilization of quartzite to replace rough granite may be in the right direction to
preserve the natural resources of conventional coarse aggregates including granite
and sandstone.
According to Abdullahi. M [33], concrete is normally produced from different
types of aggregates. The most important property of concrete is its compressive
strength. For the purpose of this research, three types of rough aggregate, i.e.
quartzite, granite and river gravel have been employed. Fine aggregate comes from
normal sand. Test results show that concrete made from river gravel has the highest
processing capacity, followed by crushed quartzite and then crushed granite. The
highest compressive strength at all days of age is achieved in concrete made from
quartzite, then concrete made from river gravel, followed by concrete made from
crushed granite.
According to Muhammad Tufail [55], concrete is a non-flammable material, yet
high temperatures still affect its mechanical properties. This study has investigated
effect of high temperatures on the mechanical properties of limestone concrete,
quartzite concrete and granite concrete. The results show that concrete made from
granite has higher mechanical properties at all temperatures, followed by quartzite
concrete and limestone concrete.
According to NIST [56], the study has expanded the comparison with aggregate
taken from 11 different quarries across the United States but mainly on the eastern
coast, and especially in the MD-VA corridor where quartzite quarries lie.
+ According to documents [52] and [61], quartzite belongs to the group of
metamorphic rock. Its mineral composition is mainly quartz. The stone is white,
light pink, yellow or gray. The stone is very hard, not easy to get weathered when


7
exposed to the air. When super-high strength concrete is studied, quartzite sand is
often used.
+ According to G. J. Verbeck and W. E. Hass [46], the CTE of a kind of
aggregate affects the CTE value of concrete containing that aggregate, meaning
the higher CTE of aggregate, the higher CTE of concrete. The CTE varies by
original stone kind with the common range from approx. 0.9×10-6/0C to 16×10-6/0C
(0.5×10-6/0F to 8.9 ×10-6/0F)
+ According to R. Rhoades and R. C. Mielenz [59], each kind of stone has
different CTE.
+ According to D. G. R. Bonnell and F. C. Harper [43], the CTE value of
concrete using quartzite cured in water environment is lower than that of concrete
using quartzite not cured.
1.7.2. Studies on quartzite and pavement cement concrete using quartzite
in Viet Nam.
+ The research on composition, mechanical properties of super-high strength
concrete and its application in bridge structures conducted by doctoral candidate
Nguyen Loc Kha [25] only mentions using quartzite sand crushed from quartzite
stone to manufacture super-high strength concrete of 120-140 MPa.
+ According to the research [22] by Prof. Pham Duy Huu and his associates at
the UTC, quartzite belongs to the group of metamorphic rock.
1.8. Conclusions of Chapter 1 and orientation for research
CHAPTER 2. INVESTIGATING AGGREGATE CHARACTERISTICS OF
QUARTZITE IN THANH SON, PHU THO AND OTHER MATERIALS
2.1. General overview of aggregate
Aggregate is a kind of granular rocky materials of natural or artificial origin,
such as sand, gravel, crushed stone, etc. of different shapes and sizes, used in the
manufacture of cement concrete, construction mortar, asphalt concrete for
pavement of railways, roadways [19], [21], [48]. In order to utilize quartzite in
Thanh Son quarry, Phu Tho province as a kind of aggregate for pavement cement
concrete production, the author has conducted an investigation into the quartzite
mining system and quartzite processing technology as presented below.
2.2. Quartzite mining system
2.2.1. Basis for selection of the quartzite mining system
Criteria for selection of the quartzite mining system in Thanh Son quarry, Phu
Tho are based on actual conditions at the quarry as stated in [2].
2.2.2. Option for quartzite mining


8

2.3. Quartzite processing technology
2.3.1. Basis for selection of the quartzite processing technology
The quartzite processing technology in application at Thanh Son quarry, Phu
Tho is selected as follows: Through blasting, raw quartzite rock is directly
excavated and transported by truck to the dam station in the North-East, where it is
crushed and sieved into sand and stone.
2.3.2. Chart of the selected technology and related parameters
Chart of the quartzite processing technology is shown in Figure 2.3. Products of
the process are quartzite stone and quartzite sand as illustrated in Figure 2.4 below.

Figure 2.4. Quartzite stone and quartzite sand

2.4. Analyzing chemical composition of quartzite in Thanh Son, Phu Tho
After studying the geological features of Thanh Son quartzite quarry, the author
conducted an analysis of the chemical composition of quartzite.
Table 2.1. Result of full analysis of chemical composition
Order
Mineral-chemical index
Outcome
Unit
1
SiO2
96.95
%
2
Fe2O3
0.32
%
3
Al2O3
1.80
%
4
CaO
0.00
%
5
MgO
0.00
%
6
SO3
0.00
%
7
K2O
0.21
%
8
Na2O
0.05
%
9
P2O5
0.00
%
The results of a full analysis of the chemical composition show that 4 substances SiO2,
A12O3, Fe2O3, K2O are notable in quartzite while other compounds are very few.
2.5.Materials for manufacturing pavement cement concrete using quartzite
2.5.1. Cement
2.5.2. Coarse aggregate and fine aggregate
2.5.2.1. Selecting and sampling for experiment


9
To provide sufficient scientific fundamentals for possibility assessment of
Thanh Son quartzite utilization in road construction, it is necessary to carry out
survey, analysis and planning of sampling.
After a field survey, the research team selected samples including coarse
aggregate of 5x10 and 10x20 quartzite stones and quartzite sand crushed from
quartzite rock as fine aggregate. Samples taken at the site were taken to the
Transport Engineering Laboratory of the University of Transport Technology to
serve the next experiments and studies. The author tested the technical
specifications of quartzite to analyze and propose possibility of using quartzite in
automobile road construction.
2.5.2.2. Coarse aggregate
Coarse aggregate is quartzite stone of 5x20, sampling as per TCVN 7572-1:2006.

Figure 2.6. Experiment to determine granular composition of aggregate
Accumulated remaining,
%

0
10
20
30
40
50
60
70
80
90
100

Particle composition
as calculated
Particle composition
as per standards
Screening size, mm

5

10

20

Particle composition
as per standards

Figure 2.7. Granular composition of quartzite stone 5x20
The test results of the technical specifications of quartzite are summarized in
Table 2.13 below. The results show the requirements (norms) set by Decision
QĐ1951[4] are satisfied.
Table 2.13. Experiment results of technical specifications of quartzite
Asses
Order
Index
Unit Norm
Testing method
Result
sment
1
Volume weight
Kg/m3 ≥ 1350 TCVN7572-6:2006
1520
Pass
2
Specific weight
Kg/m3 ≥ 2500 TCVN7572-4:2006
2633
Pass
3
Water permeability
%
≤ 2,5 TCVN7572-4:2006
0.5
Pass
4
Content of flat
TCVN7572%
≤ 15
4.05
Pass
elongated grains
12:2006
5
L.A. abrasion
TCVN7572%
≤ 30
12
Pass
12:2006
6
Strength of original
TCVN7572MPa
≥ 80
100
Pass
rock
11:2006


10
Content of weak,
TCVN7572%
≤ 1,0
0.03
Pass
weathered grains
17:2006
8
Content of dust,
%
≤ 0,3 TCVN7572-8:2006
0.21
Pass
mud, clay
9
Pressing level in
TCVN7572cylinder in saturated
%
16-20
17.58
Pass
11:2006
state
10
Softening
TCVN75720.78
Pass
coefficient
11:2006
11
Granular
TCVN7572-2:2006 Chart
Pass
composition
2.5.2.3. Fine aggregate
The fine aggregate stated in the thesis is quartzite sand. The granular
composition of quartzite sand is determined as per TCVN 7572-2:2006. The chart
of granular composition of quartzite sand is illustrated in Figure 2.10 below.
Accumulated
remaining, %

7

0
10
20
30
40
50
60
70
80
90
100

Particle composition
as calculated
Particle composition
as per standards
0.14

0.315

0.63

1.25

2.5

Screening size, mm

Particle composition
as per standards

Figure 2.10. Granular composition of quartzite sand
The test results of the physio-mechanical specifications of quartzite sand are
summarized in Table 2.18. The results show the requirements (norms) set by
Decision QĐ1951[4] are satisfied.
Table 2.18. Summary of experiment results of quartzite sand
Order
Index
Unit
Norm Testing method
Result Assessment
Volume
weight

Kg/m3

2

Specific
weight

3

Kg/m

3

Water
permeability

%


1350

2500
≤ 2.5

4

Strength of
original rock

MPa

≥ 80

1

TCVN75726:2006
TCVN75724:2006
TCVN75724:2006
TCVN757211:2006

1590
2650
1.19
100

Pass
Pass
Pass
Pass


11
Dust, mud,
%
≤ 2,0
TCVN75721.84
Pass
clay content
8:2006
6
Scale
2.2TCVN75722.94
Pass
modulus
3.5
2:2006
7
Granular
TCVN7572Chart
Pass
composition
2:2006
Remarks: The survey and experiment results of quartzite at the quarry
show that it is definitely possible to utilize this source of material for
pavement cement concrete production.
2.5.2.4. Water used for cement concrete production
The water used for cement concrete production should be good enough according to
TCVN 4506:2012 [14].
2.6. Materials for cement concrete production using limestone
To obtain a basis for research and contrast against cement concrete using
quartzite aggregate, the author has performed experiments on cement concrete
using limestone and Lo river sand. Experimental results of the technical
specifications of each material are as follows.
2.6.1. Limestone 5x20 from Minh Quang quarry, Vinh Phuc as coarse
aggregate (for contrast)
The experiment results of the technical specifications of quartzite sand are
summarized in Table 2.20 of the thesis. The results show the requirements (norms)
set by Decision QĐ1951[4] are satisfied.
2.6.2. Lo river sand in Viet Tri, Phu Tho as fine aggregate
The fine aggregate stated in the thesis is Lo river sand. The test results of the
physio-mechanical specifications of Lo river sand are summarized in Table 2.22.
The results show the requirements (norms) set by Decision QĐ1951[4] are
satisfied.
2.7. Conclusions of Chapter 2
CHAPTER 3. DESIGNING COMPOSITION OF PAVEMENT CEMENT
CONCRETE USING QUARTZITE AGGREGATE FROM THANH SON, PHU
THO AND DETERMINING COMPRESSIVE STRENGTH, BENDING
TENSILE STRENGTH, ELASTIC MODULUS
3.1. Designing composition of pavement cement concrete using quartzite
aggregate from Thanh Son, Phu Tho
3.1.1. Employing the experimental planning method to determine
influencing factors on strength of pavement cement concrete and calculating
ratio N/X.
5


12
3.1.1.1. Selecting parameters for research
a. Selecting objective functions
According to documents [30] and [31], the output norms used to evaluate
objects are often called objective functions. Experimental planning is employed for
calculation, based on the scientific experiment plan to select the cement concrete
composition in order to satisfy 2 objective functions: the compressive strength y1 =
f ( x1, x2, x1x2 ) with x1, x2, x1x2 as variables and the bending tensile strength of
cement concrete y2 = f ( x1, x2, x1x2 ) with x1, x2, x1x2 as variables.
b. Selecting influencing factors
Factors that affect the compressive strength and the bending tensile strength of
cement concrete are numerous, such as aggregate quality, cement strength, ratio
D/C and ratio X/N. Since only one kind of cement is used and only quartzite
aggregate is taken into account, the cement strength is unchanged. So, the factors
that most notably affect the two objective functions stated above are 2 elements
below:
X1: Ratio of stone upon sand (coded as D/C)
X2: Ratio of cement upon water (coded as X/N)
The experimental plan includes experimental sites, also known as plan points.
Specific values of the input factors are set at the plan points, called factor levels,
with the upper, lower and basic levels. The basic level X0j of the factors is the
experimental conditions that the researcher is particularly interested in. Along with
the input factor level, we also have to determine the changing interval (step) of
input factor ΔXj. Based on the cement concrete aggregates selected by some
countries and surveyed in some projects in Viet Nam, the author of the thesis has
chosen the variable values of 2 influencing factors X1 (1,4 ≤ X1 ≤2,0); X2 (2,5 ≤ X2
≤3,5) with X10 = 1,7; X20 = 3,0; ΔX1= 0,3; ΔX2= 0,5.
Table 3.1. Value and variable interval of influencing factors
Value
X1
X2
Variable interval
1.4 ≤ X1 ≤2,0
2.5 ≤ X2 ≤3.5
X0j
1.7
3.0
ΔXj
0.3
0.5
To facilitate calculation of experimental coefficients of the regression
mathematical model and conduct other data processing steps, we turn to
dimensionless encoded values, with the upper and lower bound values being +1 and
-1, average value: : x0j = 0 (origin of the coordinate).
Since there is no prior information, a linear description is the start. The
experiment results follow Box-Wilson's Tier 1 plan with 2 optimal levels, also
known as full-scale plan or 2k plan. The number of possible combinations of two


13
factors with two levels of N = 2k = 22 = 4. The descriptive linear regression
equation has the form: y = b0 + b1x1+ b2x2 + b12x1x2 (3.1)
3.1.1.2. Experimental plan for correlation between real code and encoded
variable
Table3.2.Experimental plan for correlation between real code and encoded variable
Option
Real code
Encoded variable
y1
y2
(MPa)
(MPa)
X1
X2
x0
x1
x2
x1x2
1
1,4
2,5
+
+
y11
y12
2
2,0
2,5
+
+
y21
y22
3
1,4
3,5
+
+
y31
y32
4
2,0
3,5
+
+
+
+
y41
y42
With y1 and y2 as the compressive strength and the bending tensile strength of
concrete, b as the descriptive parameter is determined by formula (3.2) given in the
thesis. To specify significance of the parameters, we have to repeat experiments at
the plan centre, as depicted in Table 3.3 below.
Table 3.3. Experimental plan at the centre
Option
Real code
Encoded variable
y1
y2
(MPa)
(MPa)
X1
X2
x01
x02
1

1,7

3,0

0

0

y110

y120

2

1,7

3,0

0

0

0
y21

0
y22

To determine values of y1 (compressive strength) and y2 (bending tensile
strength) for calculation by experimental planning, we have to design composition
of cement concrete and perform experiments that specify the compressive strength
and the bending tensile strength of cement concrete as described below.
3.1.1.3. Designing composition of cement concrete using quartzite from
Thanh Son, Phu Tho
The composition of cement concrete for 6 mixtures is designed as follows.
+ Mixture 1 includes Grade 40 concrete, Chinfon PCB40 cement, coarse
aggregate of quartzite rock from Thanh Son, Phu Tho, fine aggregate of quartzite
sand from Thanh Son, Phu Tho, original slump of 4cm, ratios D/C=1.4; X/N=2.5.
Mixture 1 is composed of N= 185 (litre), X = 463 (kg), C = 711 (kg), D = 996 (kg).
+ Mixture 2 includes Grade 40 concrete, Chinfon PCB40 cement, coarse
aggregate of quartzite rock from Thanh Son, Phu Tho, fine aggregate of quartzite
sand from Thanh Son, Phu Tho, original slump of 4cm, ratios D/C=2.0; X/N=2.5.
Mixture 2 is composed of N= 185 (litre), X= 463 (kg), C= 569 (kg), D = 1138 (kg).
+ Mixture 3 includes Grade 40 concrete, Chinfon PCB40 cement, coarse
aggregate of quartzite rock from Thanh Son, Phu Tho, fine aggregate of quartzite


14
sand from Thanh Son, Phu Tho, original slump of 4cm, ratios D/C=1.4; X/N=3.5.
Mixture 3 is composed of N= 150 (litre), X = 525 (kg), C = 700 (kg), D = 980 (kg).
+ Mixture 4 includes Grade 40 concrete, Chinfon PCB40 cement, coarse
aggregate of quartzite rock from Thanh Son, Phu Tho, fine aggregate of quartzite
sand from Thanh Son, Phu Tho, original slump of 4cm, ratios D/C=2.0; X/N=3.5.
Mixture 4 is composed of N= 150 (litre), X= 525 (kg), C= 560 (kg), D = 1120 (kg).
+ Mixture 5 includes Grade 40 concrete, Chinfon PCB40 cement, coarse
aggregate of quartzite rock from Thanh Son, Phu Tho, fine aggregate of quartzite
sand from Thanh Son, Phu Tho, original slump of 4cm, ratios D/C=1.7; X/N=3.0.
Mixture 4 is composed of N= 165 (litre), X= 495 (kg), C= 628 (kg), D = 1067 (kg).
+ Mixture 6 includes the same materials as Mixture 5, so its composition is the
same with N = 165 (litre), X = 495 (kg), C = 628 (kg), D = 1067 (kg)
Mixture 6 will be randomly selected for later design of cement concrete using
limestone. The reason to select the same components for cement concrete using
quartzite and cement concrete using limestone is for easy comparison and contrast.
Experiments on compressive strength, bending tensile strength, elastic modulus,
thermal expansion coefficient all adopt the composition designed for Mixture 6.
Remarks: By experimental planning, we have found the aggregate composition
of Grade 40 concrete with the data given above.
3.1.1.4. Experimenting to determine physio-mechanical properties of
pavement cement concrete using quartzite from Thanh Son, Phu Tho by
experimental planning
+ Slump is used to evaluate the easy flowing ability of concrete mix under the
effect of self-weight or vibration. Slump is specified by TCVN 3106-93 [7]. The
test resuts of slump is given in Appedix 6 and summarized in Table 3.9 below.
Table 3.9. Results of slump by experimental planning
Order
Average slump (cm)
Mixture 1
3.2
Mixture 2
3.1
Mixture 3
3.6
Mixture 4
3.7
Mixtures 5 and 6
3.4
+ Moulding, curing and selecting the size of test samples are done as per TCVN
3105-93 [6]. Images of sample moulding and curing can be seen below.

Figure 3.2. Sample moulding

Figure 3.3. Sample curing and up-picking


15
+ Experimenting to determine compressive strength and bending tensile strength
Experiments to determine the compressive strength and the bending tensile
strength of cement concrete were carried out by the author according to TCVN
3118-93 [8] and TCVN 3119-93 [9]. Images of those experiments can be seen
below.

Figure 3.4. Sample pressing
Figure 3.5. Sample bending and pulling
Experiment results of the compressive strength are summarized in Table 3.10
below.
Table 3.10. Results of compressive strength of concrete
Order
Concrete mixture
Average compressive strength (MPa)
1
Mixture 1
41.14
2
Mixture 2
43.58
3
Mixture 3
60.60
4
Mixture 4
62.50
5
Mixture 5
52.70
6
Mixture 6
50.80
Experiment results of the bending tensile strength are summarized in Table 3.11
below.
Table 3.11. Results of bending tensile strength of concrete
Order
Concrete mixture
Average bending tensile strength (MPa)
1
Mixture 1
5.26
2
Mixture 2
5.28
3
Mixture 3
6.23
4
Mixture 4
6.32
5
Mixture 5
5.81
6
Mixture 6
5.7
Remarks: The experiment results and the evaluation as per Decision QĐ1951[4]
have proved that quartzite concrete meets the requirements of bending tensile
strength.
+ Experiments of elastic modulus: The experiments were performed as per
TCVN 5276-93 [10]. To obtain data for later calculation in the next chapter, the
author conducted elastic modulus experiments for cement concrete using quartzite
aggregate of the same composition as Mixture 6 with X = 495 kg, Đ = 1067 kg, N
= 165 litre, C = 628 kg. The experiment results are illustrated in Table 3.12.


16

Sample
Sample
1
Sample
2
Sample
3

ε0

Table 3.12. Elastic modulus of quartzite concrete
σ0 (MPa)
ε1
σ1 (MPa) Elastic modulus E (MPa)

10.7 x10-6

0.05

446 x10-6

16.00

36641.4

3.8 x10-6

0.05

479 x10-6

16.00

33564.81

8.9 x10-6

0.05

437 x10-6

16.00
37257.65
ETB:
35821.29
3.1.1.5. Calculation process by experimental planning
The calculation process by experimental planning is described in detail in the
thesis. By experimental planning, the author has found the regression equations
describing the relationship between the objective functions: compressive strength
y1, bending tensile strength y2 with the influencing factor of ratio X/N. The two
regression equations are:

y1  19,19 X 2  5,62
y2  X 2  2,77

 2,5  X 2  3,5
 2,5  X 2  3,5

The formula describing the relationship between Rn and ratio X/N is:
X
Rn  19,19  5, 62
N
This formula is used to calculate ratio N/X in design of quartzite concrete
composition mentioned in the following parts.
3.1.2. Experimenting to determine compressive strength, bending tensile
strength, elastic modulus of cement concrete using limestone from Minh Quang
quarry, Vinh Phuc
To facilitate the comparison between cement concrete using quartzite and
cement concrete using limestone, as well as the calculation and analysis in the next
chapter, the author adopted the same composition design for cement concrete using
limestone as for Mixture 6 of cement concrete using quartzite with X = 495 kg, Đ =
1067kg, N = 165 litre, C = 628 kg. The test results of the compressive strength,
bending tensile strength of limestone cement concrete are given in Appendix 9
while the results of elastic modulus are given in Appendix 8 of the thesis.
Remarks: The experiments of compressive strength, bending tensile strength, elastic
modulus of cement concrete show that the quality of quartzite cement concrete is high
and equals to that of limestone cement concrete, as a result, quartzite cement concrete
can be well applicable in road construction.
3.1.3. Designing composition of cement concrete using quartzite from


17
Thanh Son, Phu Tho by method ACI 211.1.91 [34]
3.1.3.1. Designing composition of cement concrete
Grade 40 concrete is designed to be composed of coarse aggregate of quartzite
rock from Thanh Son, Phu Tho with Dmax = 20mm (stone 5x20mm), fine aggregate
of quartzite sand from Thanh Son, Phu Tho and Chinfon PCB40 cement. Ratio
N/X=0.358 is specified by the regression equation from experimental planning
(Formula 3.10). The composition of concrete mix is N=165 (litre), X=461(kg), C=
618 (kg); D=1111 (kg).
3.1.3.2. Experimenting to determine the physio-mechanical properties of
concrete
The slump of concrete was measured before sample moulding, curing and
testing. The result shows the average slump is 3.6 cm (data given in Table 3.19 of
the thesis).
+ Compressive strength: The data of the compressive strength of concrete
follows Table 3.20 of the thesis. After obtaining the experiment results, the author
conducted evaluation of the results, which yield the average strength of X  49,87
MPa, deviation S = 4.876 MPa, distribution coefficient CV  S / X  0,098 , Rđt =
Xo = X - 1.64, S=41.9 > 40, satisfying the requirements.
+ Bending tensile strength: The data of the bending tensile strength of concrete
follows Table 3.22 in the thesis. The evaluation of concrete quality as per Decision
QĐ1951[4] shows that quartzite concrete meets the requirements of bending tensile
strength.
+ Determining coefficient K in the formula (3.13) [19] describing the
relationship between the compressive strength and the bending tensile strength of
concrete. The experiment and calculation results show that coefficient K in the
experiment exceeds coefficient K as regulated, i.e. Ktn > Kqd = 0.7. Hence, in
practice, coefficient K = 0.7 is still applicable and ensures safety.
3.1.4. Conclusions of Chapter 3
CHAPTER 4. STUDYING THERMAL EXPANSION COEFFICIENT OF
CEMENT CONCRETE AND ECO-TECHNICAL EFFICIENCY OF
CONCRETE PAVEMENT UTILIZING QUARTZITE AGGREGATE FROM
THANH SON, PHU THO
4.1. Thermal behaviour of cement concrete pavement plates
4.1.1. Overview of thermal effects (impact of temperature)
4.1.2. Grounds for temperature description
4.1.3. Boundary conditions


18
4.1.4. Heat exchange model and input data
4.2. Calculation of thermal expansion coefficient
One of the impacts of temperature during concrete strength formation in a
structure is characterized by the coefficient of thermal expansion (CTE).
4.2.1. Thermal expansion coefficient of cement mortar
The CTE of cement mortar ranges from 18 to 20µ/°C.
4.2.2. Thermal expansion coefficient of aggregates
Normally, the thermal expansion coefficient of aggregates is not as high as the
CTE while the strength of Portland cement is being formed [54]. The CTE relies on
the chemical-mineral composition of aggregates [44]. The CTE of limestone is
between 4-8µε/°C while that of gravel is 7-12µε/°C [47].
4.2.3. Thermal expansion coefficient of concrete
Earlier studies show that the CTE of concrete during strength formation relies
on the volume of coarse aggregate and cement mortar [43]. By using certain type
of cement, aggregate and composition design, a formula that relates to the
relationship between the CTE and the age function of concrete is developed (4.12).
It is useful to refer to the CTE values of concrete researched by Hak Chul Shin
[49] or those set in Decision QĐ3230[5] by MOT.
4.2.4. Thermal expansion coefficient of cement concrete according to
Document [58].
Ratio X/C affects the CTE of concrete.

Figure 4.4. Relationship between CTE of aggregates and CTE of concrete [58].
Remarks: Figure 4.4 shows the CTE of limestone concrete not cured and that of
limestone concrete cured in water environment are similar, with the value of
approx. 7.2(10-6/0C). The CTE value of quartzite concrete cured in water
environment is approx. 12.3(10-6/0C) and that of quartzite concrete not cured is
approx. 12.8(10-6/0C), which is an increase of about 4% compared to water-based
curing.
4.3. Stress of cement concrete pavement
4.3.1. Stress of cement concrete pavement in early age
4.3.2. Stress of cement concrete slabs as per current standards
4.4. Formula to calculate thermal expansion coefficient of cement concrete
by AASHTO TP 60 (2006) [32]
The formula to calculate CTE is as follows.


19
(4.19)
In which, ∆La = the sample length changing in reality during temperature
changing, mm; Lo= the sample length in room temperature, mm; ∆T= variation of
temperature.
The experiment results are achieved by the average value of 2 CTEs obtained
CTE1  CTE2
from 2 experimental segments: CTE 
2
4.5. Experimenting to determine distortion and thermal expansion
coefficient of cement concrete by AASHTO TP 60 (2006)
Currently, the method of determining the CTE of cement concrete by AASHTO
T336-15 is being applied worldwide. In Viet Nam, due to the lack of qualified
samples to standardize the CTE, the doctoral candidate had to employ AASHTO
TP 60 (2006). The experiments as per AASHTO TP 60 (2006) still abode by the
regulations set in AASHTO T336-15, therefore, AASHTO TP 60 (2006) is
recommended according to document [32].
4.5.1. Experimental equipment
Sample forming and experiments were performed at the laboratory of the
University of Transport Technology with following equipment: Strain gauge SDA–
830B (TML, Japan) using LVDT measuring head, thermostatic tank, electronic
scale, thermometer, cylinder of 100 mm in diameter and 200 mm high, electronic
measuring clamp, measuring head locator.
4.5.2. Introduction of strain gauge

Figure 4.8. Strain gauge SDA - 830B
4.5.3. Preparing test samples
To facilitate comparison and contrast among aggregates, the author used
quartzite cement concrete and limestone cement concrete of the same concrete
composition X = 495 kg, Đ = 1067 kg, N = 165 litret, C = 628 kg with samples
measured by age and sample cylinder of 100 mm in diameter and 200 mm high.
4.5.4. Experimental order
The order of experiments is described in detail in the thesis.

Figure 4.12.Samples Figure 4.13.Measuring sample length Figure 4.14.Sample cooling

Figure 4.18. Operating measuring device

Figure 4.19. Data displayed on PC


20
4.6. Experiment results
The results drawn from experiments are given in Appendix 10. The results
show that quartzite concrete at Day 3, 7, 14, 28 has the CTE of 11.1925; 11.2248;
11.2200; 11.1819 (10-6/ 0C), while limestone concrete at Day 3, 7, 14, 28 has the
CTE of 7.4791; 7.3830; 7.3996; 7.4132 (10-6/ 0C).
4.7. Analysis of experiment results

CTE (10-6/OC)

CTE relies on age
12
10
8
6
4
2
0

3 Days
7 Days
14 Days
28 Days
Quartzite stone

Limestone

Figure 4.20. Relationship between CTE and age of concrete
Remarks: Basing on the experiment results and the chart in Figure 4.20, it is
obvious that the CTE of quartzite concrete and limestone concrete does not rely on
the age of concrete.

CTE (10-6/OC)

CTE relies on kind of aggregate
12
10
8
6
4
2
0

Quartzite stone
Limestone

3 Days

7 Days

14 Days

28 Days

Figure 4.21. Relationship between CTE and kind of aggregate of concrete
Remarks: The CTE of concrete relies on kind of aggregate, and the CTE of
quartzite concrete is higher than that of limestone concrete.
4.8. Analyzing effect of the size of cement concrete plates and quartzite
stone on strength and thermal stress of cement concrete pavement


21
In the thesis, the author presented the calculation of cement concrete plates as
per Decision QĐ3230[5]. While calculating cement concrete plates using limestone
and those using quartzite, the author employed the experiment results of the CTE of
limestone cement concrete and quartzite cement concrete measured at Day 28 to
compute the maximum bending tensile stress caused by thermal gradien [σtmax]
(MPa). Note that the CTE αc given in QĐ3230[5] equals to the CTE in the
experiments stated at Item 4.6 of the thesis.
4.8.1. Design calculation of pavement cement concrete slabs
4.8.2. Calculating cement concrete plates of 4.5m x 3.5m x 0.25m using
limestone
4.8.3. Calculating cement concrete plates of 4.5m x 3.5m x 0.25m using
quartzite
4.9. Result analysis
4.9.1. Analyzing effect of aggregate on concrete strength development
+ Remarks: The compressive strength of limestone concrete corresponds to
98.9% that of quartzite concrete.
4.9.2. Analyzing effect of aggregate on thermal stress development
+ Remarks: In the plate of 4m x 3.5m x 0.25m, the thermal stress in limestone
concrete achieves only 66.41% compared with quartzite concrete, and in the plate of
4.5m x 3.5m x 0.25m, the thermal stress in limestone concrete achieves only 66.23%,
compared with quartzite concrete.
4.9.3. Analyzing effect of plate size on crack resistance of cement concrete
pavement
Remarks: For cement concrete pavement using quartzite, ratio [σp,t max] / Rku %
is 16.46%; for cement concrete pavement using limestone, ratio [σp,t max] / Rku % is
11.05%. When designed of the same composition, the strength and the thermal
stress of quartzite concrete increase concurrently with those of limestone concrete.
The tensile strength increases by 1.1% and the max. thermal stress increases by
33.59%. Due to the above stated factors, concrete pavement using quartzite is more
likely to crack on the plate surface than concrete pavement using limestone at
deviation rate of cracking possibility of 5.41%. Cement concrete plates using
quartzite should be shorter than those using limestone. The cement concrete slabs
using quartzite aggregate should be 3.8m long.
4.9.4. Conclusions
4.10. Analyzing eco-technical efficiency of cement concrete pavement using
quartzite from Thanh Son, Phu Tho
4.10.1. Ability to meet requirement of strength


22
Strength is an important property of pavement cement concrete and evaluated
by means of specifications of compressive strength, bending tensile strength and
elastic modulus. The experiment results are summarized in Table 4.24 and
compared with requirements of Grade III roads as set in Decision QĐ3230 [5].
Table 4.24. Summary of concrete strength
Limestone
Order
Specifications
Quartzite concrete
Required
concrete
1
Compressive
strength
50,8
49,83
≥36
(MPa)
2
Bending tensile strength
5,7
5,64
≥4,5
(MPa)
3
Elastic modulus (MPa)
35821,29
35469,69
≥29000
4
Evaluation
Meeting the requirements
Remarks: Concrete using quartzite aggregate meets the requirements of strength
as regulated.
4.10.2. Analyzing economic efficiency
+ To analyze the economic efficiency of cement concrete pavement using
quartzite aggregate from Thanh Son, Phu Tho, the author supposed a Grade III
section with length L=1km, pavement width B = 7m and average thickness h =
0.25m. The concrete volume in need V = 1750m3. Basing on the design of
component materials for 1m3 concrete, the author calculated the material volume for
1km of road as given in Table 4.25 of the thesis.
+ To analyze the economic efficiency, the author merely evaluated the material
price with the price unit recorded in Phu Tho area in Quarter II, 2017, resulting in
the data given in Table 4.26. The results show that quartzite concrete costs
845355.94 (vnd/m3) while limestone concrete costs 917510,43 (vnd/m3).
Remarks: Quartzite concrete costs less than limestone concrete. It is possible to
utilize quartzite aggregate for concrete production so as to take advantage of the
local material of low price and boost up economic development in the region.
4.11. Conclusions of Chapter 4
CONCLUSIONS, RECOMMENDATIONS AND DIRECTION FOR
FURTHER RESEARCH
1. Conclusions
Having studied and utilized quartzite as aggregate for pavement cement
concrete, the author has come to conclusions as follows.
1.1. Affirming that quartzite rock in Thanh Son, Phu Tho is a kind of high
quality aggregate with quite large reserves of over 10 million tons, which has not


23
ever been investigated by any research to use this aggregate for pavement cement
concrete production. Exploiting and taking advantage of local materials to
manufacture concrete for road construction is imperative, aiming to reduce the
aggregate transportation that adds up to construction costs while enhance
exploitation efficiency. This material is affirmed to be in accordance with the
current standards and can be utilized to produce pavement cement concrete
(regarded only in conditions of studied norms and experiments conducted in the
thesis). Usage scope of quartzite and cement concrete using this aggregate is
limited to Grade III roads, heavy traffic roads, quartzite entirely replacing
limestone.
.1.2. By experimental planning, the author has found the regression equations
describing the relationship between the objective functions: compressive strength,
bending tensile strength with the influencing factor of ratio X/N. The two
regression equations are:

y1  19,19 X 2  5,62
y2  X 2  2,77

 2,5  X 2  3,5
 2,5  X 2  3,5

The composition of Grade 40 cement concrete using quartzite from Thanh Son,
Phu Tho has been designed as per ACI 211.1.91with ratio N/X selected by formula
(3.10), which has been established by experimental planning.
1.3. The experiment results of compressive strength, bending tensile strength,
elastic modulus, slump of cement concrete using quartzite show that quartzite
concrete achieves high quality and meets the requirements at a similar level to
limestone concrete.
1.4. Studying the thermal property of cement concrete using quartzite
Through experiments, the author has identified the distortion and the CTE of
quartzite concrete and those of limestone concrete by age with strain gauge SDA –
830B. In detail,
- Quartzite concrete at Days 3, 7, 14, 28 achieves the CTE of 11.1925; 11.2248;
11.2200; 11.1819 (10-6/0C), respectively.
- Limestone concrete at Days 3, 7, 14, 28 achieves the CTE of 7.4791; 7.3830;
7.3996; 7.4132(10-6/0C).
- Quartzite concrete has higher CTE than limestone concrete (1.5 times higher
at Day 28).
1.5. Calculation of cement concrete plates using quartzite and limestone with
expected sizes of 4m x 3.5m x 0.25m and 4.5m x 3.5m x 0.25m, according to MOT
Decision QĐ3230


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