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Many raw materials use to make the new bridges, and most of the times the owners for that kind of bridges, after some years, have to use many more raw materials, workers, and costs to maintain that. All the things are costly and time consuming. Historically, the construction has made by using four simple materials: timber, stone, concrete, and steel. In recent years, the researchers have been seeking alternative materials to concrete to less vulnerable environmental damages . This study is going to determine the appropriate materials to have Environmental, Economical, and Social characteristics by optimizing the Life-Cycle-Cost, greenhouse gas emissions, raw material uses, resources, and material production energy of bridges.
Zoom in on related work in trying to solve the current problem (this would be the literature review- should include all the references)
At 1993 "the Rio de Janeiro environmental summit injected a new urgency into the vital that economic development must be done in ways that can be sustained for future generations." Since that, the theory of "Sustainability" has become popular and many more organizations accepted that as a purposeful focus for the next centuries .
The sustainable design methodologies argue that there are some methodologies to design a more sustainable building during all phases of design, and recent studies investigated some sustainable methodologies to produce the most sustainable structure designs. These methodologies were: Reducing Embodied Energy, Life-Cycle Assessment, and Reducing Structural System Reuse .
1.1 The Characteristics of Materials in Sustainable Development
The basic rule of sustainable bridge development is to accommodate the mankind's economic and environmental acts to survive the natures. And may be summarized in a sentence: "The production processes of all products must be closed and recyclable so that no waste materials are produced.".
The role of civil engineers in Leadership in Environmental and Energy Design should not be concealed. Additionally to success of LEED , the rating system for green building construction, many owners and architects' minds must fundamentally improve the sustainability of buildings by knowing how to reduce the construction materials, emission, and Life Cycles by using the performance measurement through sustainability indicators .
One of the most problems confronting bridge is the most destructive of mechanical expansion joints, and the solution to this problem has indicated to change to continues bridge decks. Furthermore the most sustainable alternative solution is to focus on the use of Engineered Cementitious Composite (ECC) materials. According to "The durability of ECC materials plays a key role in the design of more sustainable bridge infrastructure using ECC materials".
I have to add some data from:
(Repair and Strengthening of Reinforced Concrete Beam-Column Joints with Fiber-Reinforced Polymer Composites.PDF)
The sustainable designs according to USGBC are: Environment, Economic, Health, and Community benefits. Because of that many researchers worked on these issues to be able to gain the best results .
Environmental impacts of the bridge construction are ranges large negative influence, small negative influence and no influence, and they can result to damage to resources, human health, and ecosystem quality. The previous researchers did their best to solve the current problem by investigating to the main causes of the defects. The major environmental impacts of infrastructures are during these two phases; Raw Material Processing and Construction .
- Highlight/identify the limitations/disadvantages of the related work above
From the related work above it could be observed that, there is no optimizing method for deciding the best characteristics of materials for having the sustainable bridges.
- Describe briefly your proposed technique to overcome these limitations/disadvantages (should include the methodology or architecture in brief)
As it would be mentioned, the characteristics of material for sustainable bridges are divided into three categories; Environmental, Economical, and Social aspects. Moreover to meet infrastructures (Bridges) demand without these damages, need innovative solutions. This study will fill the gap by determining the optimal method of sustainable bridges through these indicators:
Lowering life-cycle cost of bridges
Using very low GHGs emission materials for bridges
Using Recycled materials in bridge construction
Utilize the renewable resources in bridges
Utilize less material production energy
Minimizing the material uses to bridge buildings
- You may briefly introduce some results of your work
This study will introduce the innovative solutions to tackle the characteristics of materials for sustainable bridges.
- Finally the last paragraph of the Introduction, should outline the whole paper
The characteristics of materials in infrastructures, such as bridges are going to make the significant sustainable challenges in the world, especially in the developed countries. Indeed raw material consumptions for these constructions are more than the past. And to meet the infrastructure demand without Environmental, Economical, and Social damages need innovative solutions. This study will integrate some Economical, Environmental, and Social friendly aspects to optimize the best materials to construct the bridges by lowering Green-House-Gases emissions, lowering Life-Cycle-Cost, using the renewable resource, utilizing less material production energy, and minimizing the material uses of bridge buildings.
2. LITERATURE REVIEWS:
(Here I'm going to write a paragraph to define my topic)
2.1. Literature of Fiber Reinforced Polymer for bridges
The FRP is a kind of composite fiber that attached to reinforced with a fiber material, this is widely used trough the construction and reconstruction of bridges because of its most positive properties in compare to the ordinary concretes . The most pieces of bridges can be design by using FRP such as concrete beams, bridge deck panels, the cables, and tendons to gain the strength and durability of that kind of infrastructures.
In talking about FRP, they are three categories of Carbon, Glass, and Aramid.
I have to add some data from:
(Use P17 P23 P25 Advanced Composite Materials: Properties and Applications)
(A Case Study of Life Cycle Cost based on a Real FRP Bridge.pdf)
(FRP Review 2002.pdf)
(FRP Concrete Beam.pdf) AND good enough for GFRP Literature
2.2. Literature of Carbon Fiber Reinforced Polymer for bridges
Here I'm going to Literature the LCC, Fatigue, Durability, Strength, GHGs, and Energy Uses of CFRP for bridges.
In the recent decades, researchers have investigated to include environmental cost into Life-Cycle-Cost Assistant to have bridge structure sustainability.
The Carbon Fiber Reinforced Polymer (CFRP) which is used instead of reinforcement material in concrete constructions is one of the most beneficial polymers to consider the Cost and Maintenance in prestressed beam of bridges in high traffic volume areas . Additionally carbon fibers are chosen because of its compressive strength and good fatigue behaviour . Although using CFRP in the preliminary stage of concrete bridges is expensive, using of that would be achieved important reductions of Life-Cycle-Cost (95% least expensive) at year of 23-77 of bridges . According to , "the prestressed concrete bridges utilizing CFRP reinforcing bars can represent a cost effective design alternative, to ordinary steel reinforced prestressed concrete bridges". There are some models that have been tested by in LCCA such as; Activity Timing, Agency Cost, and User Cost (Fig1), to identify the lowest Life-Cycle-Cost between Black Steel Bridges and CFRP Bridges, moreover the best results were due to using CFRP bridges.
Figure1. Shows the Total User Cost of Bridges. In some cases the user costs are more than 10 times higher than the repair cost
The statistics showed that in the USA 1998, there were around 108,000 Prestressed Concrete Bridges, and according to , , (Won et al.2007), (FHWA2001), 30% of bridges require immediate repair because of corrosion of their steel reinforcement by espousing to chlorides. It is argued that one of the best materials for repairing of damaged infrastructure is CFRP, although the initial cost of that is estimated to be as much as 8 times more than that of steel . Also this literature noted that, the FRP composites are immune to chloride attack, and corrode. The concluded that Carbon fibers Reinforcement Polymers had good durability characteristics in comparison to other types of FRPs.
2.3. Literature of Glass Fiber Reinforced Polymer for bridges
Here I'm going to Literature the LCC, Fatigue, Durability, Strength, GHGs, and Energy Uses of GFRP for bridges.
In construction industry the GFP are used in a few cases, because they are neither durable and nor strong in moderate levels of stress and fatigue, besides they are used in some cases in purposes of protecting from extraneous environmental attacks, because of its ability to defense of freeze-thaw, acid , and UV light .
2.3.1. Ultimate load and Load-Deflection Behavior of GFRP
According to , the load deflection behavior of I-section beam of GFRP has been tested and the result was; the ultimate load (66 kN), moreover because of the low elastic modules of GFRP fiber, the stiffness was rather low, and it caused the higher deflection at higher level of load. (I don't know if the higher deflection for bridges is a benefit or weakness?)
And I have to add some data from: (glass-fiber reinforced polymer (GFRP) bars exhibit large deflections in comparison with steel-reinforced concrete beams because of the low modulus of elasticity of GFRP bars. This paper proposes new equations for estimating the effective moment of inertia of FRP-reinforced concrete beams on the basis of the genetic algorithm and experimental results).
2.3.2. Mechanical Properties:
The found that, the best mechanical result for GFRP will appear, when each fiber of the GFP has the diameters ranking between 3 and 9 micrometers. Additionally the GFPR materials demonstrate the appropriate mechanical properties (such as; compressive strength, creep resistance) and in compare to other fiber composites they are economical.
I have to add some data from (Seismic Behavior of Beam-Column Joints Reinforced with GFRP Bars and Stirrups.pdf)
2.4. Literature of Geopolymer Cements for bridges
Here I'm going to Literature the LCC, Fatigue, Durability, Strength, GHGs, and Energy Uses of Geopolymer Cements for bridges.
Geopolymer cement made from Fly ash, Metallurgical Slag, and Natural Pozzolan and it could be reduced the amount of Green-House-Gases emission by the appropriate formulating. The 5% of CO2 emission globally is because of cement industry, furthermore this is the second most consumed substance on earth after water . According to , by adoption of Geopolymer cement instead of Portland cement the CO2 emission related to manufacturing cement will be reduced by 80%, additionally the Geopolymer cement has been tested by them in the prestressed concretes, and the results were satisfied. The 90 percentages of the total CO2 emissions of cement products are because of the cement clinker. concludes that due to production of 1 tone Portland cement, between 0.8 to 1.0 tone of CO2 and 3.5 Kg NOx will be emitted to the atmosphere.
The significant of lower chloride diffusion and acceptable freeze-thaw performance of Geopolymer Cement has been shown by (Zeoband's E-Crete) in comparison with Portland cement. The previous studies show that; the majority bridge structures constructed by Geopolymer concrete can present the environmental sustainable alternatives because of reducing Embodied Energy, CO2 emissions, Carbon Footprint, and Global Warming Potential . There is a reason for widely uncertainty in embodied energy, for instance between two factories that manufacture the same product, the same embodied energy will produced per kilograms of products. But the total carbons emitted are different because of the mix of fuels consumed by factories were not same .
The Geopolymer concrete provides significant improvement in the design stages, and it recommended being heat cured. Some positive effects of using this alternative material are listed in table 1 .
1. Low carbon emission
5. Remarkable LCC saving
2. Longer service life
6. Recycle industrial waste
3. Reduce global warming potential
7. Minimal or negligible maintenance
4. Reduce use of virgin materials
8. Sustainable construction
Table1- The positive characteristics of using Geopolymer concrete in bridges
High Strength Concrete
Concrete Cover (mm)
Table2- The durability of High Strength Concrete (HSC) and Geopolymer Concrete in bridges
Additionally, according to Table2 concludes that, in uncracked concretes, the corrosion would be started after 7.6 years in High-Strength concretes and more than 1,000 years in Geopolymer Concretes.
Geopolymer concrete can reach to its 70% of the final compressive (8-100Mpa) strength in the first four hours of setting; also it is more durable than Portland, it possesses excellent engineering properties, and lower carbon footprint than Portland (Li et al. 2004, Gourley and Johnson 2005, Rangan 2008).
. According to (Palomo et al. 1999; Muntingh 2006; Song 2007; Rangan 2008), "the Geopolymer cement has a superior chemical resistance against Sulphates, Chlorides, and Acids".
2.5. Literature of Ultra-High Performance Concrete
Here I'm going to Literature the LCC, Fatigue, Durability, Strength, GHGs, and Energy Uses of Ultra-High Performance Concretes...
2.6. Literature of Recycled Concrete Aggregate
Here I'm going to Literature the LCC, Fatigue, Durability, Strength, GHGs, and Energy Uses of Recycled aggregate Concretes...
4. FINDING AND DISCUSSION
4.1. The Expected Result of This study is:
Less Material Production Energy
Minimizing Raw Material Uses
Life cycle cost definition: LCC
"The total cost throughout its life including planning, design, acquisition, support cost and any other cost directly attributable to owning or using the asset."
Carbon footprint definition:
"Total amount of green house gases produced directly or indirectly as a result of an activity"