DEVELOPMENT OF SELF-CONSOLIDATING MICRO CONCRETE UTILIZING WLP
By Odu Paul Duku Erikole
Interim Report submitted in partial fulfilment of the requirements for the Bachelor of Engineering (Hons) (Civil Engineering)
May 2013
Universiti Teknologi PETRONAS Bandar Seri Iskandar 31750 Tronoh Perak Darul Ridzuan
ABSTRACT
Conventional concrete is normally compacted by using vibrators yet insufficient compaction could lead to inclusion of voids which in turn leads to a reduction in compressive strength of the concrete. Compaction of concrete also produces noises and has health and safety risks as operators are subjected to white finger syndrome. The consequences associated with compaction have led to the development of selfcompacting concrete (SCC), a concept first initiated in Japan in the mid-1980s to offset a growing shortage of skilled labor. Self-compacting concrete (SCC) does not require vibration for placing and compaction but it is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. Furthermore, natural aggregates such as crashed rocks used in concrete are non-renewable and such resources are depleting. Last but not least, WLP which is being produced in large quantities by Lynas Plant is normally dumped in landfills and landfills destroy wildlife habitats as well as reduce agricultural productive land. The objectives of this project are 1) to develop self-consolidating micro-concrete (SCMC) utilizing WLP as micro-aggregates and 2) to determine the physical, mechanical and durability properties of the newly developed SCMC utilizing WLP. Using SCC lowers concrete construction costs and time, reduces noise pollution and injuries related to vibration work of concrete, allows for concreting in heavily congested structural elements and improve finish surface quality. The use of WLP of particle sizes below 600 microns as micro-aggregates and in the absence of coarse aggregates reduces the amount of cement required for the mix, improves the particle packing density of the mix, thereby, enhancing the rheological and mechanical properties as well as durability of resulting self-compacting micro concrete. Last but not least, using WLP in concrete reduces landfill usage hence conserves wildlife habitats and agricultural land. The project work consists of preparation of trial mixes in the concrete laboratory until a mix of the SCMC utilizing WLP satisfying the requirements of SCC is obtained. Mixing for different water/cement ratios and different quantities of WLP will then be carried out,
I
followed by testing for the mechanical properties and durability of the SCMC utilizing WLP.
TABLE OF CONTENTS
ABSTRACT ................................................................................................................. I TABLE OF CONTENTS .................................................................................................II LIST OF FIGURES ...................................................................................................... IV LIST OF TABLES ........................................................................................................ IV ABBREVIATIONS AND NOMENCLATURES .................................................................. V CHAPTER 1: INTRODUCTION ......................................................................................1 1.1.
Project Background ...................................................................................................................1
1.2.
Problem Statement ...................................................................................................................2
1.3.
Significance of the project .........................................................................................................3
1.4.
Objectives and Scopes of Work .................................................................................................3 1.4.1. Project Objectives .................................................................................................................... 3 1.4.2. Project Scope ........................................................................................................................... 4
1.5.
Feasibility of the project within the scope and time frame ........................................................4
CHAPTER 2: LITERATURE REVIEW ...............................................................................5 2.
2.1. Self-consolidating concrete (SCC) ............................................................................................5
3.
2.1.1. Definition and properties of SCC ..........................................................................................5
4.
2.1.2. Test Methods and Acceptance Criteria .................................................................................6
5.
2.1.3. Mixture Proportions of SCC ..................................................................................................9
2.1.4.
Material characteristics and proportions to produce SCC ..........................................................9 2.1.4.1. Aggregates ...................................................................................................................... 10 2.1.4.2. Cement and fine fillers ................................................................................................... 10 2.1.4.3. Admixtures ..................................................................................................................... 10 2.1.4.4. Paste Volume .................................................................................................................. 11
II
2.1.4.5.
Paste Composition. ......................................................................................................... 11
2.1.5.
Rational mix design method – Okamura and Ozawa (1995). ...................................................11
2.2.
Hardened Properties of SCC ....................................................................................................12
2.3.
Self-Consolidating Micro-Concrete (SCMC) ..............................................................................12
2.4.
Self-Consolidating Micro-Concrete (SCMC) utilizing WLP.........................................................12
CHAPTER 3: METHODOLOGY .................................................................................... 14 3.1.
Materials .................................................................................................................................14
3.2.
Project activities ......................................................................................................................15
3.3.
Mix Design ..............................................................................................................................18
3.4.
Key milestone..........................................................................................................................19
3.5.
Gantt Chart .............................................................................................................................20
3.6.
Tools or equipment required. ..................................................................................................20
CHAPTER 4: CONCLUSION AND RECOMMENDATIONS .............................................. 22 REFERENCES ............................................................................................................ 23
III
LIST OF FIGURES Figure 1: Slump and Slump flow measurement for Conventionally Placed Concrete (left) and SCC (right) respectively. ............................................................................................. 6 Figure 2: Basic principles for production of self-compacting micro concrete (Upadhyay, Shah & George, 2011). ...................................................................................................... 9 Figure 3: Summary of the project methodology ............................................................ 17
LIST OF TABLES Table 1: List of test methods for workability properties and acceptance criteria for Selfcompacting Concrete (SCC) .............................................................................................. 8 Table 2 Chemical Composition of Ground WLP............................................................. 13 Table 3 Chemical Composition of Sieved WLP .............................................................. 13 Table 4 Chemical Compositions of OPC and FA ............................................................ 14 Table 5 Chemical Compositions of Sieved Raw WLP .................................................... 15 Table 6 Mechanical and durability properties to be tested. ............................................. 16 Table 7: Trial mix proportions for self-consolidating micro concrete utilizing WLP ... 18
IV
ABBREVIATIONS AND NOMENCLATURES
SCC……………Self-Consolidating Concrete/Self-Compacting Concrete HPSP…………..High Performance Super Plasticizer
SF………………Silica Fume
FA………………Fly Ash
MIRHA…………Microwave Incinerated Rice Husk Ash
GGBS…………...Ground Granulated Blast Furnace Slag
MC………………Micro Concrete
CRMs……………Cement Replacement Materials
VMAs……………Viscosity Modifying Admixtures
sec…………….….Seconds
min……………….Minutes
Min.…………….....Minimum
Max.………………Maximum
w/c…………………Water-Cement Ratio
w/cm……………….Water-Cementitious Materials Ratio
w/p………………….Water-Powder
V
Ratio
CHAPTER 1: INTRODUCTION
1.1.
Project Background
Concrete is the most widely used man made construction material in the world, and is second only to water as the most utilized substance on the planet (Gambhir, 2004). Conventional concrete or generally known as concrete is a mixture of cement, aggregates (coarse and fine aggregates) and water (and sometimes admixtures). When the mixture in a required proportion is placed in forms and allowed to cure, it hardens as a result of the chemical reaction between the cement and water into a rock like mass hence concrete. The characteristics of concrete such as strength, durability just a few to mention depend on the properties of its ingredients, mix proportions, method and degree of compaction, handling during placement, curing and so on. For example, insufficient compaction will lead to inclusion of voids which in turn leads to a reduction in compressive strength of the concrete. Compaction of concrete also produces noises and has health and safety risks as operators are subjected to white finger syndrome. The consequences associated with compaction have led to the development of self-compacting concrete (SCC), a concept first initiated in Japan in the mid-1980s to offset a growing shortage of skilled labour (Choo, 2003). Murthy et al (2012) defined Self-compacting concrete (SCC) as an innovative concrete that does not require vibration for placing and compaction but able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. According to Murthy et al (2012), the hardened concrete is dense, homogeneous and has the same engineering properties and durability as traditional vibrated concrete. The constituents of SCC include Portland cement and filler like limestone powder, coarse aggregates of nominal size 10mm, fine aggregates, chemical admixtures such as high performance super plasticizer (HPSP), mineral additive such as silica fume (SF), fly ash (FA) and ground granulated blast furnace slag (GGBS), water and super plasticizers all mixed in a known proportion.
1
Using SCC results into several benefits hence the following considerations:
Increased productivity levels by shortening concrete construction time
Lower concrete construction costs by decreasing the labor and equipment needed on construction sites
Improved working environment due to reduced noise pollution and injuries related to vibration work of concrete
Improved in-situ concrete quality in difficult casting conditions such as heavily congested structural elements and hard-to-reach areas.
Improved surface quality (higher-quality finish surfaces is easily achieved using SSC).
This project aims at developing self-consolidating micro concrete (SCMC) utilizing Limed Water Leach Purification residue (WLP) from Lynas Plant as micro aggregate. Lynas Plant/Corporation is an Australian based mining company having rare earth processing plant, called Lynas Advanced Materials Plant (LAMP) in Gebeng industrial estate in Kuantan, Malaysia. Micro Concrete (MC) is a high performance cement-based material proportioned with micro-aggregates whose particle sizes range from about 0.5 mm to less than 1µm (Felekoglu, 2007). MC is a matrix phase including all fines (cement, pozzolanes and fines in aggregates), water and possible chemical admixtures (Felekoglu, 2007. The incorporation of WLP as micro-aggregates is expected to improve the particle packing density of the mix, thereby, enhancing the rheological and mechanical properties of the SCMC. 1.2.
Problem Statement
The durability of concrete depends on its relatively high compressive strength which in turn depends on the techniques or degree of compaction. The compaction of concrete is normally done by vibrators, by inexperienced labor force and supervision of compaction is normally difficult, all these factors contribute to insufficient compaction leading to inclusion of voids which in turn leads to a reduction in compressive strength of the concrete. Compaction of concrete also produces noises and possess health and safety risks like white finger syndrome to the operators. 2
Furthermore, natural aggregates such as crashed rocks used in concrete are nonrenewable and such resources are depleting. Last but not least, WLP which is being produced in large quantities by Lynas Plant is normally dumped in landfills and landfills destroy wildlife habitats as well as reduce agricultural productive land. 1.3.
Significance of the project
This project involves the development of self-consolidating micro concrete utilizing WLP. The use of Self-compacting concrete (SCC) which does not require vibration for placing and compaction but is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement is an innovative solution to the durability problems of concrete associated with reduced compressive strength due to inadequate compaction. Apart from increase in durability of concrete structures, the use of SCC also shortens concrete construction time, lowers concrete construction costs by decreasing the labor and equipment needed on construction sites, improves working environment due to reduced noise pollution and injuries related to vibration work of concrete, makes it easier to concrete heavily congested structural elements and hard-to-reach areas, and results into a higher-quality finish surfaces. Furthermore, the use of WLP whose particle sizes range from about 0.5 mm to less than 1µm as micro-aggregates and in the absence of coarse aggregates improves the particle packing density of the mix, thereby, enhancing the rheological and mechanical properties as well as durability of resulting self-compacting micro concrete. Last but not least, using WLP in concrete reduces landfill usage hence conserves wildlife habitats and agricultural land. 1.4.
Objectives and Scopes of Work 1.4.1. Project Objectives
2.
To develop self-consolidating micro-concrete utilizing WLP as micro-aggregates
3.
To determine the physical, mechanical and durability properties of the newly developed self-consolidating micro-concrete utilizing WLP 3
1.4.2. Project Scope In order to achieve the objectives of this project, the effects of both
water-cement ratio and
proportions of WLP in the total mix
on the mechanical and durability properties of self-consolidating micro-concrete utilizing WLP as micro-aggregates are examined. Mechanical properties tests consists of compressive and tensile strengths tests will be conducted at the age of 7 and 28 days, while leachate test together with the durability tests such as permeability, porosity and chloride ion tests will be carried out at the age of 28. For each tests, three cubes are cast per mix. 1.5.
Feasibility of the project within the scope and time frame
The total duration for this project is two semesters. Scope of work for the first semester ends with the submission of this interim report and as soon as the second semester starts, the remaining project tasks (mixing, testing of mechanical and durability properties and final report writing) will be done. Based on the work plan for executing the project scope of work as shown in the Gant Chart in appendix, the duration of the project is sufficient for all the project works to be completed.
4
CHAPTER 2: LITERATURE REVIEW
2.
2.1. Self-consolidating concrete (SCC)
3.
2.1.1. Definition and properties of SCC
Murthy et al (1012) defined Self-compacting concrete (SCC) as an innovative concrete that does not require vibration for placing and compaction but able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. Fresh SCC is characterized by filling ability, passing ability, and segregation resistance. According to Koehler & Fowler, (2007);
Filling ability describes the ability of concrete to flow under its own mass and completely fill formwork.
Passing ability describes the ability of concrete to flow through confined conditions, such as the narrow openings between reinforcing bars.
Segregation resistance describes the ability of concrete to remain uniform in composition during placement and until setting.
Segregation resistance includes both static and dynamic stability. Static stability describes segregation resistance when concrete is at rest. Dynamic stability describes segregation resistance with concrete is not at rest—such as during mixing and placing. Apart from the ability of SCC to flow and consolidate under its own weight, ability to pass through tight spaces, such as between reinforcing bars, without the assistance of vibration and ability to resist segregation as opposed to conventionally placed concrete, the horizontal flow of SCC is measured as compared to the conventional slump test, where the change in height of the specimen is determined upon removal of the slump cone (Figure 1).
5
Figure 1: Slump and Slump flow measurement for Conventionally Placed Concrete (left) and SCC (right) respectively.
4.
2.1.2. Test Methods and Acceptance Criteria
Several different test methods have been developed in attempts to characterize the properties of SCC. Schutter, (2005) has recommended the following four reference methods for European standardization to measure the properties of fresh self-compacting concrete: i.
Slump flow test (total spread and T50 time) which is primarily used to assess filling ability and is suitable for both laboratory and site use
ii.
L-box test, primarily to assess passing ability is suitable for laboratory use
iii.
J-ring test is primarily to assess passing ability and is also suitable for both laboratory and site use
iv.
Sieve stability test to assess segregation resistance is suitable for laboratory and site use
Schutter, (2005) also recommended the following tests as alternative methods for European standardization: 6
i.
V-funnel test: partially indicates filling ability and blocking, suitable for laboratory and site use
ii.
Orimet test: partially indicates filling ability and blocking, suitable for laboratory and site use
iii.
Penetration test: to assess segregation, possibly used in combination with the sieve stability test
The final selection of recommended test methods was based mainly on their relation to one or more of the key properties of self-compacting concrete (filling ability, passing ability, and resistance to segregation) as well as on reproducibility and repeatability (Schutter, 2005). The advantages and disadvantages of each method in terms of cost, portability, simplicity of operation and other practical aspects also affect the selection of each test methods. Table 1 summarizes the list of test methods for workability properties and acceptance criteria for Self-compacting Concrete (EFNARC, 2002).
7
Table 1: List of test methods for workability properties and acceptance criteria for Self-compacting Concrete (SCC)
Typical range Application Test Method
Property
Units
Lab
Field
(Mix
(QC)
of
values Min. Max.
design) by Filling ability
mm
650
800
T50cm slump flow Filling ability
sec
2
5
J-ring
Passing ability
Mm
0
10
V-funnel
Filling ability
Sec
6
12
V-funnel at T5min
Segregation
Sec
0
+3
Slump-flow Abrams cone
resistance L-box
Passing ability
(h2/h1)
0.8
1.0
U-box
Passing ability
(h2-h1)
0
30
%
90
100
%
0
15
sec
0
5
mm Fill-box GTM
Passing ability screen Segregation
stability test
resistance
Orimet
Filling ability
8
5.
2.1.3. Mixture Proportions of SCC
Mixture proportions can vary depending on the available materials and placement conditions, the workability and hardened property requirements, and the mixture proportioning procedure used (Koehler & Fowler, 2007). Normally more than one acceptable mixture proportioning is possible for a given set of materials and application requirements and mixture proportions that perform successfully in one plant are likely to be of little relevance for a different plant having different materials. Whether or not a concrete will meet the requirements of SCC depends on the properties of the combined aggregates, the paste volume, and the composition of the paste. Utsi, (2008), concludes that successful mix design for SCC involves: (1) increasing the filler content, (2) decreasing the course aggregates content and (3) adding a high water reducing agent. Figure 2 illustrates the basic principles for production of selfcompacting micro concrete. Absence of coarse aggregates
Reduction of waterpowder ratio (w/p)
High segregation resistance of mortar and concrete
Usage of super plasticizers
High deformability of mortar and concrete
Self-Consolidating micro concrete
Figure 2: Basic principles for production of self-compacting micro concrete (Upadhyay, Shah & George, 2011).
2.1.4. Material characteristics and proportions to produce SCC In order to produce a mix proportion that meets the requirements of self-compacting concrete, there is need to understand the material characteristics and proportions to produce SCC. The material used in SCC consists of: 9
2.1.4.1.Aggregates Both gravel and crushed rock of maximum size 20 mm and minimum size 10 mm are used as coarse aggregates to produce SCC (Choo, 2003). It is advisable to reduce the coarse aggregate size because passing ability and segregation resistance may be improved by reducing the maximum aggregate size. According to Koehler & Fowler (2007), the sand-aggregate (S/A) ratio is normally between 0.40 and 0.50 for SCC. Higher S/A ratios are typically associated with improved passing ability and segregation resistance. Although the use of higher S/A ratio results in lower coarse aggregate volume, it may allow a lower paste volume. (p.10). Severely gap-graded aggregate blends should be avoided because it affects segregation. Well-rounded aggregates with few or no flat or elongated particles allow the use of lower paste volume and result in lower viscosity and lower high-range water-reducing admixture (HRWRA) demand. Texture does not affect workability significantly; however, it can affect hardened properties substantially (Koehler & Fowler, 2007). 2.1.4.2.Cement and fine fillers Portland Cement (PC) and fine particle binders such as PFA and GGBS are normally used in SCC mixes. PFA and GGBS are added to increase workability of the fresh concrete, reduce PC contents and lower heat of radiation. Limestone powder is also being used to offset the increased fine contents requirements of SCC. Although it does not significantly contribute to the compressive strength development of SCC, limestone powder will maintain stability in a high workability mix and will control the heat of hydration in mixes with high PC content (Choo, 2003). 2.1.4.3.Admixtures Viscosity modifiers or viscosity modifying admixtures (VMAs) can be added to increase resistance to segregation while still maintaining high fluidity, allowing concretes to flow through narrow spaces (Choo, 2003).
10
2.1.4.4.Paste Volume The paste volume, which can range from 28% to 40% is used to produce SCC. It is advisable to use the minimum paste volume in SCC so as to achieve the required workability. This minimum required paste volume primarily depends on the aggregate characteristics. Koehler & Fowler (2007) point out that well-shaped and well-graded aggregates with high packing density require significantly less paste volume thus resulting into improved hardened properties and economy, however, using higher paste volumes than the minimum required, which increases flow ability. 2.1.4.5.Paste Composition. The paste composition is defined in terms of the relative amounts of water, powder, and air and the blend of powder. Here, there is need to consider: Water Content; WaterCement Ratio (w/c); Water-Cementitious Materials Ratio (w/cm) which mainly relates to long-term hardened properties; Water-Powder Ratio (w/p) that ranges from 0.25 to 0.45 or higher and is equal to the w/p if no non-cementitious powders are used; Cement Content, mineral fillers and air content which ranges from 1-2% for non-air entrained concrete. 2.1.5. Rational mix design method – Okamura and Ozawa (1995). This mix design method was developed in Japan in 1995 and was based on the fact that self-compactability of concrete can be affected by the characteristics of the materials and mix proportions. The mix design method consists of the following basic steps (Choo, 2003). i.
Fixing the coarse aggregate content at 50% of the solid volume of the concrete
ii.
Fixing the fine aggregate content at 40% of the mortar volume
iii.
Assuming the water/binder ratio to be 0.9 – 1.0% by volume depending on the properties of the binder(s)
iv.
Determining the super plasticizer dosage and final water/binder ratio so as to ensure self-compatibility.
11
2.2. Hardened Properties of SCC According to Murthy et al (2012), the hardened concrete is dense, homogeneous and has the same engineering properties and durability as traditional vibrated concrete. Choo (2003) however, reported that the compressive strength of SCC is usually higher than for conventional concrete due to the lower water/binder ratios associated with SCC. Selfcompacting concrete that has been well designed and produced is homogeneous, mobile, resistant to segregation and able to be placed into formwork without the need for compaction thus leading to minimal interfacial zones development between coarse aggregates and the mortar phase as compared to conventional concrete. Therefore, the microstructure of SCC can be expected to be improved, promoting strength, permeability, durability and ultimately a longer service life of the concrete (Choo, 2003). 2.3. Self-Consolidating Micro-Concrete (SCMC) Felekoglu (2007), defined Micro Concrete (MC) as a high performance cement-based material proportioned with micro-aggregates whose particle sizes range from about 0.5 mm to less than 1µm. The incorporation of micro-aggregates improves the particle packing density of the mix, thereby, enhancing the rheological and mechanical properties of MCs. SCMC mix consists of Ordinary Portland cement and fly ash as binder, WLP as micro-aggregate and polycarboxylate based super plasticize to improve flow-ability. Design mix for SCMC is just similar to that of SCC except that no coarse aggregates are used and the best mix for SCMC is obtained through the optimization of water/cementitious material ratios and super plasticizers dosage. 2.4. Self-Consolidating Micro-Concrete (SCMC) utilizing WLP Generally speaking, the application of WLP in concrete is totally a new innovation. In this project, the WLP is used as micro aggregates. Because WLP is very fine, using it in the mix is expected to result into improvement of workability and a very dense hardened micro-concrete with enhanced strength and durability. The WLP used can either be ground (G) or sieved (S). Ground WLP basically involves drying the WLP under the sun before grinding it with L.A. abrasion machine. The chemical composition of the ground WLP as obtained in the Earth Material Characterization Laboratory of Universiti Sains Malaysia are summarized in the Table 2 below. 12
Table 2 Chemical Composition of Ground WLP Chemical Composition
WLP RAW (G)
WLP 3000C (G)
WLP 5000C (G)
WLP 7000C (G)
SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 Total
8.64 0.89 2.69 28.96 0.11 0.11 2.21 0.36 0.48 20.91 65.36
9.76 0.91 2.81 30.23 0.11 0.11 2.27 0.40 0.44 21.31 68.35
11.42 0.95 3.01 31.48 0.11 0.11 2.34 0.48 0.48 22.51 72.90
9.30 1.02 2.79 33.59 0.12 0.14 2.50 0.33 0.42 24.09 74.30
Sieved WLP on the other hand involves drying the WLP using the same method as for ground WLP but then, crushing it manually before sieving it using 600 micron sieve. Table 3 summarizes the Chemical Composition of Sieved WLP also obtained in the Earth Material Characterization Laboratory of Universiti Sains Malaysia
Table 3 Chemical Composition of Sieved WLP Chemical Composition
WLP RAW (S)
WLP 3000C (S)
WLP 5000C (S)
WLP 7000C (S)
SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 Total
5.82 0.95 2.08 32.61 0.11 0.12 1.73 0.35 0.16 20.85 64.78
5.46 0.97 2.08 33.41 0.11 0.13 1.75 0.19 0.15 21.49 65.74
6.51 1.07 2.36 36.50 0.12 0.13 1.85 0.23 0.22 23.14 72.13
6.08 1.07 2.37 37.07 0.12 0.14 1.82 0.20 0.17 23.45 72.49
13
CHAPTER 3: METHODOLOGY
3.1.
Materials
The materials used in this project include: 1.
An ordinary Portland cement (CEM 142.5R)
2.
A type C fly ash (FA)
3.
WLP of size below 600 µm
4.
A polycarboxylate based super plasticizer with a solid content of 35.7% to improve flow ability.
5.
Clean mixing water
The chemical compositions of Ordinary Portland Cement (OPC), fly ash (FA) and Sieved Raw WLP are summarized in Tables 4 and Table 5.
Table 4 Chemical Compositions of OPC and FA Percentage (%) Chemical Composition SiO2 Al2O3 Fe2O3 CaO MgO SO3 K2O Na2O
OPC
Fly Ass
20.3 4.2 3 62 2.8 3.5 0.9 0.2
56.39 17.57 9.07 11.47 0.98 0.55 1.98 1.91
14
Table 5 Chemical Compositions of Sieved Raw WLP Chemical Composition
Sieved Raw WLP
SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O TiO2 MnO P2O5
5.82 2.08 32.61 1.73 0.12 0.16 0.35 0.95 0.11 20.85
3.2.
Project activities
First, trial mixes are prepared by dry mixing the constituents: sand, cement, fly ash and WLP for about 30 s in a Hobart mixer. Water and super plasticizers are then added and the mixing is continued for 2 min. At this stage, characteristic tests for self-compacting concrete especially slump flow; J-ring and V-funnel are then conducted If the results for slump flow; J-ring and V-funnel tests conducted does not meet the requirements for self-compacting concrete, another trial mix is prepared with adjusted water/cementitious materials (w/cm) and super plasticizer dosages until those requirements are met. Cubes (Table 6), are then cast to be used for the determination of the mechanical and durability properties of the developed self-consolidating micro concrete utilizing WLP as micro aggregates. The method used for the execution of this project work is as summarized in Figure 3 below.
15
Table 6 Mechanical and durability properties to be tested. Mechanical Properties Compressive Tensile Strength Strength Development test Test at 7 and Test at 28 days, 3 and samples for days, each age samples each age
Leachate Test
Durability Properties Permeability Porosity
Chloride Ion test
7 3 samples 3 samples 3 samples 3 samples 28 per mix at per mix at per mix at per mix at 3 28 days 28 days 28 days 28 days for
16
Start Preparation of constituent materials
Mixing
Testing for fresh concrete properties
Fulfills requirements for SCC?
Yes Testing for hardened concrete properties Analysis of results of hardened concrete properties Conclusion and Recommendations
End Figure 3: Summary of the project methodology
17
No
3.3.
Mix Design
Table 7 shows the trial mix proportions to be used for the development of the selfconsolidating micro concrete utilizing WLP as micro aggregates. Table 7: WLP
Mix ID
Trial mix proportions for self-consolidating micro concrete utilizing
w/c ratio WLP
PC (kg/m3)
(kg/m3)
Water
SP (kg/m3)
(kg/m3)
M1
0.26
300
380
98.8
3.05
M2
0.26
400
380
98.8
3.05
M3
0.26
500
380
98.8
3.05
M4
0.26
600
380
98.8
3.05
M5
0.27
300
380
102.6
3.05
M6
0.27
400
380
102.6
3.05
500
380
102.6
3.05
600
380
102.6
3.05
0.27 M7 0.27 M8 M9
0.30
300
380
114
3.05
M10
0.30
400
380
114
3.05
M11
0.30
500
380
114
3.05
M12
0.3
600
380
114
3.05
w/c - water cement ratio PC- Portland Cement SP- Super Plasticizer
18
3.4.
Key milestone
Activities
Durations (weeks)
1. Reading of Articles
Week 2-3
2. Writing Literature Review
Week 4
3. Writing Research Methodology
Week 5
4. Attending Laboratory Safety Briefing
Week 6
5. Mobilization of Required tools/equipment
Week 6
6. Ordering materials and sample preparation
Week 7-10
7. Trial Mixing and selection of Mix Design
Week 11
8. Mixing
To be continued in FYP 2
9. Results and Discussions
To be continued in FYP 2
10. Final Report Writing
For FYP 2
19
3.5.
Gantt Chart
3.6.
Tools or equipment required.
To effectively carry out the necessary activities for this project from mix design to the testing of the properties of both fresh and hardened fiber reinforced self-consolidating micro concrete, the following tools (machineries and equipment are needed. 1.
Concrete mixer
2.
Concrete cube moulds 20
3.
Concrete cylindrical moulds
4.
Curing tank
5.
Slump-flow, Abrams cone
6.
T50cm slump flow test apparatus
7.
J-ring test apparatus
8.
Compressive strength testing machine
9.
Flexure testing machine
21
CHAPTER 4: CONCLUSION AND RECOMMENDATIONS
The objectives of this project are to develop self-compacting micro concrete utilizing WLP as micro aggregates and to determine the mechanical as well as durability properties of the newly developed self-compacting micro concrete utilizing WLP as micro aggregates. When the mechanical and durability properties of the newly developed self-compacting micro concrete is found to be improved, such concrete will be recommended for use in real projects. The use of self-compacting micro concrete utilizing WLP as micro aggregates in real projects will mean using a large volume of WLP in the concrete industry and thus reducing usage of landfills leading to the conservation of wildlife habitats and valuable agricultural land. It will also replace total reliance on natural aggregates hence conserves non-renewable resources. The total construction cost for projects will also be lowered because using self-compacting micro concrete reduces the number of labor and equipment at construction sites. Extra precautions need to be taken when manually breaking down WLP into small pieces and when performing any other activities involving WLP because being very fine (below 600 microns), WLP can easily become an air borne. It is recommended that face mask and hand glove be worn every time when handling WLP and that ear protection equipment be used while sieving the WLP.
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REFERENCES 1.
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