HIGH STRENGTH CONCRETE FOR SUSTAINABLE CONSTRUCTION

434 HIGH STRENGTH CONCRETE FOR SUSTAINABLE CONSTRUCTION Wu, D. 1, Sofi, M. 1 Mendis, P. 1 1 Department of Civil and Environmental Engineering, University of Melbourne, Vitoria, Australia. E-mail: d.wu11@ugrad.unimelb.edu.au Telephone: +61 3 83447244; Fax: +61 3 83444616 Abstrat: The use of HSC for onstrution, espeially for multi-story buildings, has beome very ommon in industrialized and developing ountries. In view of gaining popularity as a onstrution material, high strength onrete (HSC) properties are disussed in this paper. A brief review of literature is presented. The neessary ingredients of HSC suh as fly ash, slag and silia fume whih are mostly industrial byproduts make the produt environmentally friendly. The main engineering properties of the HSC are also reviewed. Keywords: High Strength Conrete, Engineering Properties, Environment 1. Introdution During the past few years, high-strength onrete (HSC) has been generating inreased interest amongst ivil and strutural engineers. The expanding ommerial use of this relatively new onstrution material an be explained partially by the life yle ost-performane ratio it offers, as well as its outstanding engineering properties, suh as higher ompressive and tensile strengths, higher stiffness and better durability, when ompared to the onventional normal strength onrete (NSC). From a historial point of view, in the middle of the 20th entury onrete with harateristi strength (f ) of 25MPa was onsidered high-strength. In the 1980s, 50MPa onrete was onsidered high-strength. About two deades ago, HSC was mostly speified for projets as an alternate design. But today, HSC is being speified in the preliminary design stage as a sensible solution for onrete onstrution. Nowadays, tehnology for produing HSC has suffiiently advaned suh that onretes with ompressive strengths of up to about 120MPa are ommerially available, and strengths muh higher than that an be produed in the laboratories. The signifiant eonomi advantages of HSC are very well-doumented, and evident from the number of reent onstrution projets where HSC has been used suessfully [1]. The use of HSC for onstrution, espeially for multi-story buildings, has beome very ommon in industrialized and developing ountries. In Australia, where the majority of buildings are onrete strutures, almost all onrete high-rise and medium-rise building projets utilize HSC. Australia has taken the advantage of the benefits of high-strength onrete [2, 3] through its widespread use on buildings suh as 120 Collins Street, Melbourne Central, the Rialto projet in Melbourne, the 43- storey high Casselden Plae projet in Melbourne. In Seattle USA, the strength of onrete used on the Paifi First Centre was about 125MPa [4]. The Freedom Tower in New York City, whih will be one of the world s tallest superstrutures, is projeted to be ompleted in 2010. The struture onsists of a robust high-strength onrete ore paired with a highly redundant perimeter steel moment resisting frame. Most experiene on HSC in Europe has been gathered in Norway, with that ountry s development in offshore platforms, bridges, and highway pavements [5]. In Germany, HSC was first utilized in a high-rise building in Frankfurt, ompleted in 1992. HSC with a mean strength of 100 MPa was used in the Petronas Towers in Kuala Lumpur in 1998. The Eureka Tower, whih is one of the tallest buildings in Australia was ompleted in 2006 has utilized HSC up to 100 MPa. In general, onrete is not onsidered as a sustainable onstrution material in terms of large onsumption of raw materials, ontribution to greenhouse gas emissions from ement and low durability. The ruling argument is that the prodution of 1kg of ement whih, is the main ingredient of onrete, generates 0.8-0.9kg of CO 2 emission [6]. It is ommonly argued that with a high growth rate, the demand for onrete onsumption will substantially inrease in the near future imposing a heavy burden on the eologial system. The CO 2 emission related to onrete prodution, inlusive of ement prodution is between 0.1 and 0.2tonne per 1tonne of produed onrete [7]. The

435 environmental impat of onrete as a onstrution produt is questionable with studies demonstrating onrete produts requiring muh less energy with a lower net environmental impat when ompared to other onstrution materials suh as steel [8]. Regardless of the impat to the environment, it is a true fat that urrently urbanization worldwide relies heavily on the onrete industry. Worldwide, some 6 billion tons of onrete is produed per year, making onrete one of the world s most popular onstrution materials. On the eonomial front, this represents about 13 to 14 trillion USD world trade dealing [9]. In view of the importane of limate hange, sustainability has beome the main onern for the onrete industry. In order to assess the environmental impat of onrete, a multi-dimensional, lifeylle approah is adopted [9, 10]. The findings show that, when onsidering the life-yle stages of the produt into onsideration in order to arry a omprehensive and impartial assessment, onrete an be onsidered as a material that burdens the environment least [11]. It is further reported that using high performane onrete has multiple environmental benefits. For instane, it is possible to build a durable struture with minimum maintenane that lead to a redution in the onsumption of raw materials and greenhouse gas emissions, and relaiming industrial waste produts and using them as effetive onstrution materials [11]. In spite of this, steps have been taken in plae to redue the CO 2 emissions into the atmosphere. In order to limit the usage of Portland ement, the onrete industry has been inreasingly inlined towards substituting Portland ement with fly ash, slag and miro silia fume all whih are industrial byproduts. It is believed that this substitution an be inreased without impairing the performane of the onrete grades [10]. This paper presents literature review of urrent studies undertaken on HSC. The review is divided into two parts. In the first part, the main onstituents of HSC are presented. The main ingredients whih influene the performane of HSC are disussed (Setion 2). The addition of mineral admixtures whih are mostly industrial by-produts is ommon in the prodution of HSC. The effets of these admixtures on the onrete properties are also disussed. On the seond part, the engineering properties of HSC onrete are presented (Setion 3). For the purposes of this paper, HSC is defined as onrete with ompressive strength, f, in the range of 50-100 MPa. NSC is onrete with f < 50 MPa. 2. High strength onrete onstituents The sustainable high performane onrete does not ontain any speial or unusual ingredients. A ommon mix inludes Portland ement, super plastiizers, silia fume, fly ash and slag, with relatively large amount of ementitious by-produts for ement replaement. The signifiane of eah material in produing high strength onrete is disussed in this setion. 2.1. Water/binder (w/b) ratio and ement ontent HSC usually ontains one or two mineral additives whih are used as partial replaement for ement. Therefore, the term water/ement (w/) ratio used in referene to normal strength onrete (NSC) is replaed by w/b ratio, where the binder is the total weight of the ementitious materials (ement + additives). The minimum w/b ratio for full hydration of ement pastes is approximately 0.36 [12]. For NSC this limit is usually exeeded for workability requirements. However, in the ase of HSC, omplete hydration is not essential for full strength to be attained and therefore it an be made with w/b ratios less than 0.36. HSC s have been made with w/b ratios as low as 0.2. However, high dosages of superplastiizers are required to maintain workability [13]. Patnaikuni and Patnaik [12] suggests that a w/b ratio of 0.23 is an optimum value for maximum ompressive strength of very high-strength onrete mixes. The inorporation of mineral admixtures suh as silia fume, fly ash, slag or rie-husk ash is ommon in prodution of HSC onrete. These ementations by-produts failitate the manufature of highstrength onrete.

436 2.2. Mineral admixtures Silia fume Silia fume is a by-produt of the manufaturing proess of silion and ferrosilion alloys and is in a form of glass whih is highly reative. The small size of partiles will aelerate the reations with alium hydroxide whih enables silia fume to replae Portland ement for a small proportion. The major purpose of introduing silia fume to the onrete mix is to ahieve high strength and durability. The presene of silia fume also enhanes the effetiveness of superplastiizer, whih onsequently redues w/b ratio required to ahieve a ertain level of workability [14]. Normally, 3 to 10% of silia fume is used for high performane onrete. Behnood & Ziaria [15] found that the silia fume has more pronouned effets on ompressive strength than a derease in w/b ratio. The optimal value for silia fume and w/b were estimated to be 6% and 0.35 respetively. In an experimental study, Ting et al. [16] onluded that about 10% replaement of ement by silia fume is the optimum dosage. Fly ash Fly ash is a by-produt of the ombustion of pulverised oal in thermal power plants. It is removed as a fine dust by mehanial extrators, eletrostati preipitators or fabri filters. Fly ash an be inluded into onrete either blended with ement or diretly introdued as an additional ementitious material at the onrete mixing plant. Typial appliations are in pumped or in superplastiised onretes, partiularly where heat of hydration is onsidered to be a problem. The introdution of fly ash has effets on many properties suh as workability, hydration, strength development shrinkage, heat evolution and durability. The inlusion of fly ash in the onrete mix redues the water ontent required to produe a ertain level of workability. Experimental studies by Jiang and Malhotra [17] have found the redution of water ontent an be as high as 20%, if high quality of fly ash were used. Fly ash generally has adverse effets on onrete strength, espeially at the early age. However, fly ash may have better performane when the w/b ratio is low. It has been demonstrated that at w/b=0.5, a 45% fly ash resulted in about 30% redution in 28-days strength, but at w/b ratio=0.3, the redution in strength is redued to 17% [18]. So far, it is possible to add 50% or more fly ash to replae Portland Cement to ahieve sustainable high strength onrete with less than 130 kg/m 3 water ontent and 200kg/m 3 ement ontent. Slag Slag is a by-produt material obtained from pig iron in the blast furnane and is formed by the ombination of earthy onstituents of iron ore with limestone flux. The presene of slag develops the workability and strength of onrete. Generally, the dosage rate of slag is between 15% and 30% of the ementitious material [19]. In fresh onrete, slag tends to improve the workability of the onrete due to their angular shape and smooth surfae texture. Consequently, the required amount of superplastiizer ould also be redued by inreasing slag ontent [20]. It has been shown that the ompressive strength of onrete inreases with inreasing amount of opper slag when superplastiizer is not applied [21]. 2.3. Coarse Aggregates As ompared to NSC, the mineralogy and the rushing strength of oarse aggregates has a signifiant effet on the strength of a HSC mix. Aording to Setunge [22], higher strength aggregates do not neessarily produe higher-strength onretes. A more desirable property is the ompatibility of the stiffness of the aggregates and the mortar. The ideal material will be rushed rok with low stiffness and high strength. It is generally observed that smaller aggregates are desirable to produe high strength onrete due to redution in the water aumulating near the oarse aggregates and larger available surfae area for bonding with ement matrix. For ommerial appliations, taking into

437 aount the eonomy of prodution, workability and shrinkage and reep, well graded aggregates of 14-20mm size are reommended. Aitin [23], for the purposes of disussion divided high-strength onrete and very high-strength onrete into five ategories and disussed the relative importane of various fators on the strength of onrete. The first three ategories are summarized in Table 1. Table 1: Categories of HSC [23] Category Strength Category I 50 75MPa Manufatured using good quality, but generally used materials, existing prodution tehnology and w/b ratio of about 0.4. Mineral admixtures are not required. Superplastiizers may be used to ahieve the required workability, Category II 75 100MPa High quality, generally used materials are required. Due to the very low w/b ratio of about 0.25-0.30, superplastiizers are required to ahieve adequate workability. The use of mineral admixtures is also strongly reommended. The oarse aggregates must be round or ubi in shape. Category III 100-125MPa Very high quality materials, effiient mixing tehniques and stringent quality ontrol needed. The w/b ratio must be lowered to 0.22-0.25. High dosages of superplastiizers are essential in onjuntion with silia fume. The other two ategories refer to 125 MPa and beyond and will not be disussed here as they are not ommonly used and diffiult to ahieve in the field. 2.4. Superplatiizers Superplastiizers are essential to produe good workable high-strength onrete. There are, basially three prinipal types of superplastiizers: (i) lignosulfonate-based (ii) melamine sulfonate and (iii) naphthalene sulfonate. In general, a ombination of the above types is used for high-strength onrete. The amount of superplastiizer to be added to a mix is governed by the required workability. 2.5. Curing De Larrad [25] reports that self-desiation is probable in HSC and hene speimens ured in water will absorb water, thus inreasing the strength of the onrete. An opposite view is expressed by some who argue that water evaporation from a NSC ylinder is greater than that from a HSC ylinder. Therefore, the strength development of a NSC ylinder will be more affeted by defiient uring than the strength development of a HSC ylinder. Studies by Aitin [26] on uring of HSC show that HSC members have a delayed response to strength gain. Aitin suggests that due to the low permeability of high-strength onrete it takes onsiderable time for water to penetrate the onrete and ontribute to the hydration proess, hene longer periods of moist uring of HSC speimens is reommended. 3. Engineering properties of HSC The aim of this setion is to provide an overview of the strutural engineering properties and harateristis of HSC, in light of the reent experimental and theoretial researh and published results. There are other non-strutural benefits of using HSC, for example the improved durability of the material whih is a result of redued porosity and the use of high-quality materials. However, the topi of durability is not disussed here in detail. 3.1. Compressive strength Enhaned ompressive strength is the most important of HSC s funtional properties. Admixtures suh as silia fume or fly ash are not essential to the manufature of high-strength onrete with ompressive strengths loser to 50 MPa. However, the inorporation of these mineral admixtures,

438 partiularly silia fume does failitate the proess and silia fume is also essential to produe very high-strength onrete. The main reason for the spetaular inrease in onrete strength in silia fume onrete is the reation of a dense onrete matrix enabled by the uniformly distributed fine silia fume partiles in between larger ement partiles. The use of superplastiizers and good ompation by vibration aids in the densifiation proess lead to the higher strength. Aording to de Larrad and Malier [26], the mirostruture of high-strength onrete is very dense and amorphous and ontains very little free water. It has a very low-porosity and laks the aumulation of lime rystals, as in the ase of NSC. 3.2. Charateristi Prinipal Tensile strength The tensile strength of HSC is signifiantly greater than that of NSC, though to a lesser extent than the ompressive strength. Frature surfaes are smooth, indiating the homogeneity of the material. The densifiation of the onrete matrix and the aggregate-matrix transition zone explains the improvement of the tensile strength. The harateristi flexural tensile strength, f f, and the harateristi prinipal tensile strength, f t in aordane to various standard proedures are summarized in Table 2.The reommended values are plotted against f in Figure 1. Table 2: The harateristi flexural tensile strength (f f ) and the harateristi prinipal tensile strength (f t ) aording to various standards Standard Reommendations for f f and f t AS3600-2001 [27] f ' = 0. 6 f ' (1) f f ' t = 0.4 f ' (2) AS3600-2009 [28] f ' = 0. 6 f ' (3) ACI 318-2005 [29] ACI 363R [30] Euroode EC2-2004 [31] f f ' t = 0.36 f ' (4) f ' = 0.62 f ' (5) f t f ' = 0.59 f ' (6) f + 8 f ' = 2.12ln 1 + (7) t 10 f f = max [(1.6-h/1000)f t ; f t ] (8) Where h is the depth of the ross setion (a) f f (b) f t Fig.1: The harateristi flexural tensile strength (f f ) and the harateristi prinipal tensile strength (f t ) aording to various standards 3.3. Modulus of Elastiity The modulus of elastiity (E ) of HSC is dependent on parameters suh as the volume of aggregates, the modulus of the paste and the modulus of the aggregates. The reommendations for E values aording to various standard proedures and researhers are summarized in Table 3 and plotted in Figure 2.

439 Setunge [32] has shown that the existing AS3600-2001 formula (Eq (9)) has the tendeny to overestimate the elasti modulus of HSC. The new AS3600-2009 reommends Eq. (9) to estimate the modulus of elastiity of onrete up to 40 MPa. However, for onrete strength greater than 40 MPa, the new ode reommends Eq. (10) to predit the elasti modulus of onrete. Table 3: The modulus of elastiity aording to various standards and researhers Standard Reommendations for E * AS3600-2001 [27] E = 0.043ρ 1.5 f ' ± 20% (9) AS3600-2009 [28] E = ρ 1.5 (0.024 f ' + 0.12) ± 20% (10) ρ E 3 (11) 2320 ACI 318-2005 [29] = (.32 f + 6895) E Euroode EC2-2004 [31] = 22 10 3 0. 3 f 10 (12) Mendis et al. [33] E = 0.43ηρ 1.5 f ' ± 20% where, η = 1.1-0.002f 1.0, (13) ρ = (14) 2320 * The nominal density of normal weight HSC ρ = 2400 kg/m 3 Carrasquillo et al. [32] E ( 3320 f ' + 6900) 1.5 1.5 Fig. 2: Modulus of elastiity (E ) values aording to various standards and researher 3.4. Required over for durability It is noted in the ommentary of AS3600 that arbonation and ionisation (an inrease in the reative ion onentration suh as hloride) are two fators that will influene durability in terms of orrosion of steel. HSC onsists of a more uniform mirostruture and lower porosity ompared to NSC. This indiates a higher resistane to penetration of CO 2 and Cl ions into the onrete, thus reduing the orrosion of steel reinforement. However, during prodution of HSC, maroraking due to plasti shrinkage, miroraking due to self-dessiation and thermal raking may represent potential problems from a orrosion protetion point of view. HSC s are also being speified for a range of ritial ivil engineering strutures where the durability properties of the onrete are of paramount onsideration and where design life requirements of over 100 years are needed. It is therefore prudent to also adopt the over values speified in AS3600 for 50 MPa onrete for onrete strengths higher than 50 MPa. However the designers may redue the over values aording to Table 4. It must be noted that for f < 70 MPa, the same values as given in AS3600 [28] are reommended.

440 Table 4: Required Cover Values Exposure Standard Formwork Rigid Formwork and Spun or Rolled Classifiation and Compation are Intense Compation Members (Table used (Table 4.10.3.2 are used (Table 4.10.3.5 of AS3600[28]) of AS3600[28]) 4.10.3.4 of AS3600[28]) f < 70 f 70 f < 70 f 70 f < 70 f 70 MPa MPa MPa MPa MPa MPa A1 20 20 15 15 10 10 A2 20 20 15 15 10 10 B1 25 20 20 15 15 10 B2 35 30 25 20 20 15 C 50 45 40 35 25 20 3.5. Fire resistane of HSC Fire resistane of onrete members is normally aomplished by strutural adequay and insulation for a speified fire resistane period. Several researhers have onluded that with the exeption of spalling, whih is defined as the detahment of piees of onrete when a onrete member is exposed to fire. there is no apparent reason to treat high-strength onrete differently from lower strength onrete. Spalling an take plae over the whole surfae area of a member or in loalised areas [38]. The risk of spalling is higher in high-strength onrete due to the following reasons: 1 Low permeability of HSC retains the moisture inside the onrete resulting in a high moisture ontent being present for prolonged periods. 2 Low porosity of HSC reates higher pore pressure. 3 HSC tends to be subjet to higher ompressive stresses than lower strength onrete. In 1996, a omprehensive investigation was onduted at the National Institute of Standards and Tehnology, on experimental and analytial studies on fire performane of HSC. The key findings and a literature review are given by Phan [35]. It was observed that onrete with dense pastes resulting from the addition of silia fume are more suseptible to explosive spalling. HSC made with lightweight aggregate appears to be more prone to explosive spalling than HSC made of normal weight aggregate onretes. Chan et al. [36] showed that moisture ontent and strength are the two main fators governing explosive thermal spalling of onrete. Also, HSC speimens heated at higher heating rates, suh as hydroarbon fire whih ourred in WTC ollapse on September 11, and larger speimens are more prone to spalling than smaller speimens heated at lower rates. Aording to the review by Phan [35], the material properties of HSC vary differently with temperature as ompared to those of NSC. The differenes are more pronouned in the temperature range of between 25 C to about 400 C, where higher strength onretes have higher rates of strength loss than lower strength onretes. These differenes beome less signifiant at temperatures above 400 C. Compressive strengths of HSC at 800 C derease to about 30% of the original room temperature strengths. The tensile strength versus temperature relationships dereases similarly and almost linearly with temperature for HSC and NSC. HSC mixtures with silia fume have higher strength loss with inreasing temperatures than HSC mixtures without silia fume. There are only a few studies reported reently on the strutural behaviour of HSC members subjeted to fire. Meda et al. [37] studied the ultimate behaviour of HSC setions at high temperature and after ooling subjeted to several fire durations. They onluded that HSC setions are more temperaturesensitive than NSC setions. However, the differene is not signifiant. Kodur [38] reommended design guidelines for mitigating spalling and enhaning fire endurane of HSC olumns. In a reently onluded projet at the University of Melbourne, Ta [39] found that HSC will go through more pronouned explosive spalling under hydro-arbon fire ompared to standard fire.

441 4. Conluding Remarks The onstituents of HSC have been disussed. It is noted that the neessary ingredients making the onrete suh as fly ash, slag and silia fume are mostly industrial byproduts whih are otherwise wasted in landfills. This should be onsidered towards reognition of HSC as an environmentally friendly material. The main engineering properties of HSC are reviewed in the paper. Referenes 1. Mendis, P., Design of High-strength Conrete Members-State-of-the-art, EA Books, 2001.. 2. Choy, R. S., "High-Strength Conrete." Tehnial Report No. TR/F112, Cement and Conrete Assoiation of Australia, Sydney, 1988. 3. Smith, G. J., and Rad, F. N., "Eonomi Advantages of High-Strength Conretes in Columns." Conrete International: Design and Constrution, 11(4), 1989, pp. 37-43. 4. Randall, V., and Foot, K. "High-Strength Conrete for Paifi First Center." ACI Conrete International: Design and Constrution, 11(4), Detroit, USA, 1989, pp. 14-16. 5. Konig, G., Bergner, H., Grimm, R., and Simsh, G, "Utilization of High-Strength Conrete in Europe." Germany, 1993, pp 45-56. 6. www.eo-serve.net visited on 28 th of Otober, 2010 7. Glavind, M. and Munh-Petersen, C., Green onrete in Denmark, Strutural Conrete, Vol 1, Issue 1, 2007, pp. 1-7. 8. Struble, L. and Godfrey, J., How Sustainable is onrete?, Proeedings of International workshop on Sustainable development and onrete tehnology, Beijing, 2004. 9. Lippiatt, B. and Ahmad, S., Measuring the life-yle environmental and eonomi performane of onrete: the bees approah, Proeedings of International workshop on Sustainable development and onrete tehnology, Beijing, 2004. 10. Nielson, C. V. and Glavind, M., Danish experienes with deade of green onrete, Journal of Advaned onrete tehnology, Vol 5, Issue 1, 2007, pp. 3-12. 11. Lounis, Z.; Daigle, L., Environmental benefits of life yle design of onrete bridges, 3 rd Int. Conf. on Life Cyle Management, Zurih, Switzerland, Aug, paper, pp. 1-6, 2007. 12. Patnaikuni I. and Patnaik, A.K., Design and Testing of High-Performane Conrete Int. onferene of Rehabilitation, Renovation, Repair of Strutures, Visakhapatnam, India, 1992. 13. Mak, S.L., Defining Performane and Basi Considerations for Materials and Mix Design, Proeedings of a workshop on Tehnology, Design and Appliations of HSC/HPC at the University of Melbourne, Australia, Ed. P. Mendis, Feb. 1994. 14. Neville, A. M. Properties of onrete, New York, Wiley, 1996. 15. Behnood, A., and Ziaria, H, "Effets of silia fume addition and water to ement ratio on the properties of high-strength onrete after exposure to high temperatures" Cement and Conrete Composites 30(2), 2007, pp. 106-112. 16. Ting, E.S.K., Patnaikuni, I., Pendyala, R.S. and Johanson, H.A., Effetiveness of Silia Fumes available in Australia to Enhane the strength of Very High Strength Conrete, International onferene on The Conrete Future, Kuala Lumpur 1992. 17. Jiang, L.H., and Malhotra.V, Redution in Water Demand of Non Air-Entrained Conrete Inorporating Large Volume of Fly Ash. Cement and Conrete Researh 30, 2000, pp. 1785-1789. 18. Lam, L., Wong, Y. L. and Poon, C. S., Effet of Fly Ash and Silia Fume on Compressive and Frature Behaviors of Conrete, Cement and Conrete Researh, 28(2), 1998, pp.271-283. 19. Mehta, P. K., High-Performane, High-Volume Fly Ash Conrete for Sustainable Development, International Workshop on Sustainable Development and Conrete Tehnology. Beijing, 2004. 20. Yazii, H. Y., Mert, Y. Y., Yiğiter, H., Aydin, S., Türkel, S., "Mehanial properties of reative powder onrete ontaining high volumes of ground granulated blast furnae slag." Cement and Conrete Composites 32(8): 639-64, 2010. 21. Wu, W., Zhanga, W. and Guowei, M., optimum ontent of opper slag as a fine aggregate in high strength onrete, Materials & Design, 31(6), 2010, pp. 2878-2883. 22. Setunge, S., Engineering Properties of High-Performane Conrete, Proeedings of a workshop on Tehnology, Design and Appliations of HSC/HPC at the University of Melbourne, Australia, Ed. P. Mendis, Feb. 1994. 23. Aitin, P.C., How to Make High-Performane Conrete, Presented at the High-Performane Conrete Seminar, National University of Taiwan, Taipei, 1992. 24. de Larrard, F, A Mix Design method for High-Strength Conrete, pro. Conf. First International Symposium on utilisation of High-strength Conrete, Stavanger, Norway, 1988.

442 25. Aitin, P.C., High-performane Conrete, E & FN Spon, UK, 1998. 26. de Larrard, F and Malier, Y, Engineering Properties of Very High Performane Conretes High- Performane Conrete - From Material to Struture,(Editor- Malier), E&FN Spon, 1994, London, pp 85-114. 27. AS3600, "Conrete Strutures", Australian Standard, Standards Assoiation of Australia, Sydney, 2001. 28. AS3600, Conrete Strutures, New Australian Standard, Standards Assoiation of Australia, Sydney, 2009. 29. ACI 318. Building Code Requirements for Strutural Conrete and Commentary, Amerial Conrete Institute, Mihigan, 2005. 30. ACI Committee 363, "State of the Art Report on High-Strength Conrete (ACI 363R-92, Reapproved 1997)", Amerian Conrete Institute, Farmington Hills, Mih., 1997, 54 pp. 31. Euroode 2: Design of Conrete Strutures. Part 1. General Rules and Rules for Buildings, 2004. 32. Setunge, S. Engineering properties of High-Strength Conrete, Ph.D thesis, Monash University, 1993. 33. Mendis, P.A, Pendyala, R.S. and Setunge, S. Requirements for High-Strength Conrete in AS3600, High- Performane Conrete Sub-ommittee of the Conrete Institute of Australia, 1997. 34. Carrasquillo R.L., Slate F.O., Nilson A.H., "Miroraking and Behaviour of High Strength Conrete Subjeted to Short Term Loading", ACI Journal, Vol.78 (3), May-June 1981, pp 179-186. 35. Phan, L.T., Fire Performane of High-Strength Conrete: A Report of the State-of-the-Art, NISTIR 5934, National Institute of Standards and Tehnology, Gaithersburg, 1996, 105 pp. 36. Chan, S.Y.N., Peng, G.F. and Anson, M. Fire Behaviour of High-Performane Conrete made with Silia Fume at Various Moisture Contents, ACI Materials Journal, Vol.96, No.3, 1999, pp. 405-411. 37. Meda, A., Gambarova, P.G. and Bonomio, M. High-Performane Conrete in Fire-Exposed Reinfored Conrete Setions, ACI Strutural Journal, Vol.99, No.3, 2002, pp. 277-287. 38. Kodur, V.K.R. Guidelines for Fire Resistane Design of High-Strength Conrete Columns, Journal of Fire Protetion Engineering, Vol.15, No.2, 2005, pp. 93-106. 39. Ta, B, The behaviour of normal and high-strength onrete subjeted to hydroarbon fire, PhD Thesis, University of Melbourne, 2009.