Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٤٤ PRODUCTION OF SELF COMPACTING CONCRETE FOR CIVIL ENGINEERING STRUCTURES Abstract During the last decades new cementations materials were available, that led to new types of concrete. This represent a sort of technical revolution with respect to the traditional concrete. In this paper atraditional concrete (slump 170mm & little bleeding) , and two self compacting concrete( slump flow 700mm &neglectful bleeding) mixes were manufactured, ordinary Portland cement content(400kg/m3) and w/c ratio 0.45 used in manufacturing concretes, in order to obtain the same 28 day compressive strength .SCC were made with different types of mineral additions as fillers ,in this paper ground limestone and very fine sand used. The concrete specimens were wet cured at room temperature till the test age. Compressive strength of SCC were higher than that of the traditional concrete ,this can be related with a change in the microstructure of the cement matrix caused by the small particles of the limestone and very fine sand, which increase the density of cement paste and reduce the voids in it. Key words: Concrete, Self compacting concrete, new concrete materials ,limestone, super-plasticizer, fine sand. ذاتیة الرص لمنشات الهندسة المدنیة خرسانةإنتاج نهاد طارق خشین علیاء مریح محمد الرضا عباس ریاض عبد مدرس مساعد مدرس مساعد مساعد أستاذ كلیة -جامعة بغداد كلیة الهندسة - جامعة بغداد كلیة الهندسة -المثنىجامعة الهندسة الخالصة لقد تواجدت خالل العقود السابقة مواد إسمنتیة جدیدة أدت إلى ظهور أنواع جدیدة من الخرسانة وهذا یمثل إن. إلى الخرسانة التقلیدیة" نوع من الثورة التقنیة قیاسا . أهم أنوع الخرسانة المبتكرة هي خرسانة ذاتیة الرص من خرسانة ذاتیة الرص إلى نوع خاص من خلیط الخرسانة یتمیز بالمقاومة العالیة لالنعزال والذي یشیر مصطلح Dr.riyad a. abass College of engineering al-muthena university alyaa m.mohammed College of engineering Baghdad university nihad t.khshain College of engineering Baghdad university Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٤٥ حیث . إن الخرسانة ذاتیة الرص تحد من الحاجة إلى الرج الداخلي والخارجي. یمكن إن یصب بدون رص أو رج تكتل حیث یمكن إن تكون أنها تجري بحریة في داخل وحول التسلیح الكثیف وتملئ القالب بشكل كامل بدون أي في هذا . أخرى عندما یكون الرص غیر مالئم ةمادة مثالیة للصب ألموقعي للركائز واألسس ومنشآت خرسانی جریان الهطول (و نوعین من خرسانة ذاتیة الرص ) ملم ونضوح قلیل١٧٠هطول (تم عمل خرسانة تقلیدیة البحث من % ٤٥سمنت /متر مكعب ونسبة ماء/كغم ٤٠٠نت خلطت باستخدام محتوى سم) ملم و نضوح مهمل ٧٠٠ یستخدم في عمل خرسانة ذاتیة الرص أنواع عدیدة من . یوم ٢٨اجل الحصول على نفس المقاومة بعمر عولجت عینات الخرسانة . في هذا البحث استخدم حجر كلسي مطحون ورمل ناعم جدا. المضافان كمالئات تم دراسة مقاومة انضغاط الخرسانة ذاتیة الرص . حین عمر الفحصمعالجة رطبة في درجة حرارة الغرفة إلى وهذا یر جع للتغیر الحاصل في هیكل بنیة ةباستخدام المواد المدرجة أعاله فكانت اكبر من الخرسانة االعتیادی و التي زادت من كثافة عجینة "عجینة االسمنت بسبب الحبیبات الصغیرة للحجر الكلسي والرمل الناعم جدا . سمنت وقللت الفراغات فیهااال Introduction The most important innovative concrete is Self-Compacting Concrete (SCC), the term Self-Compacting Concrete (SCC) refers to a special type of concrete mixture characterized by high resistance to segregation, that can be cast without compaction or vibration. SCC eliminates the need for internal or external vibration, as it freely flows in and around dense reinforcement and fills the mold completely without any blockages. it would be an ideal material for casting in situ piles, foundations, and other concrete constructions where compaction is infeasible. Concrete is the most widely consumed material in the world, after water. Placing the fresh concrete requires operatives using slow, heavy, noisy ,expensive, energy consuming mechanical vibration to adequate compaction to obtain the full strength and durability of hardened concrete[European Union Growth , 2005]. For several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest in Japan. To make durable concrete structures, sufficient compaction by skilled workers is required. However, the gradual reduction in the number of skilled workers in Japan's construction industry has led to a similar reduction in the quality of construction work [Collepardi,2002]. One solution for the achievement of durable concrete structures independent of the quality of construction work is the employment of self-compacting concrete, which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. The necessity of this type of concrete was proposed by Okamura in 1986,Studies to develop self-compacting concrete, Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٤٦ including a fundamental study on the workability of concrete, were carried out by Ozawa and Maekawa at the University of Tokyo [Collepardi,2002]. The prototype of self-compacting concrete was first completed in 1988 using materials already on the market. Self compacting concrete (SCC), which have been developed and exploited over the past one a half decades eliminates the need for slow, heavy, noisy ,expensive ,energy-consuming and often dangerous mechanical vibration to compact the fresh concrete. In structural members with high percentage of reinforcement it fills also completely voids and gaps. it flows like “honey “and has nearly a horizontal concrete level after placing. self compacting concrete is defined so that no additional inner or outer vibration is necessary for the compaction. SCC is compacting it self alone due to its weight and deaerated almost completely while flowing in the formwork[Shah,2005]. Environmentally friendly (SCC) could be produced and used , with benefits to the construction process to the workers, and to people living near construction sites. With respect to the traditional concretes, the new cementations materials, thanks to the availability of new raw materials, allow the concretes to reach much higher performances in terms of execution on job sites, useful service life, and mechanical strength these new raw materials include: • New synthetic polymers (poly-acrylates) which, with respect to naphthalene- or melamine-sulphonated polymers, are able to reduce even more effectively the amount of mixing water and then the water-cement ratio with all the consequent benefits [Corinaldesi,Orlandi and Moriconi,2002] • Viscosity modifying agents based on Welan Gum to produce thixotropic mixes and then to obtain cohesive fresh concretes even when very fluid [European Union Growth,2005] • Polymeric metallic fibers to increase the ductility and the fracture energy of concretes which usually are brittle materials [Corinaldesi,Orlandi and Moriconi,2002] • Mineral additions characterized by amorphous silica such as silica fume (waste from silicium-iron alloys) in form of very fine particles (size of some nm/m) or UFACS Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٤٧ (Ultra-Fine Amorphous Colloidad Silica) synthetically produced in form of particles (size of some nm). With regard to its composition, self-compacting concrete consists of the same components as conventionally vibrated normal concrete, which are cement, aggregates, water, additives and admixtures. However, the high amount of super- plasticizer for reduction of the liquid limit and for better workability, the high powder content as “lubricant” for the coarse aggregates, as well as the use of viscosity-agents to increase the viscosity of the concrete have to be taken into account. In principle, the properties of the fresh and hardened SCC, which depend on the mix design, should not be different from normal concrete . One exception is only the consistency. Self-compacting concrete should have a slump flow s>65cm. The present procedure for the production of self-compacting concrete is predominantly empirical. The mix design is based on experience from Japan, the Netherlands, France and Sweden. For the production of SCC, the mix design should be performed so, that the predefined properties of the fresh and hardened concrete are reached for sure. The components shall be coordinated one by one so that segregation, bleeding and sedimentation is prevented [European Union Growth,2005]. The most important basic principle for flowing and cohesive concretes including SCC is the use of super plasticizer combined with a relatively high content of powder materials in terms of Portland cement, mineral additions, ground filler and/or very fine sand. Since the development of the prototype of self-compacting concrete in 1988, the use of self compacting concrete in actual structures has gradually increased. The main reasons for the employment of self-compacting concrete can be summarized as follows: · to shorten construction period. · to assure compaction in the structure: especially in confined zones where vibrating compaction is difficult. · to eliminate noise due to vibration: this is effective especially at concrete products plants. That means the current condition of self compacting concrete is a “special concrete” rather than standard concrete. Currently, the percentage of self compacting concrete in Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٤٨ annual product of ready mixed concrete in Japan is around 0.1% [Okamura and Ouchi,1999] . A typical application example of Self-compacting concrete is the two anchorages of Akashi-Kaikyo(Straits) Bridge opened in April 1998, a suspension bridge with the longest span in the world (1,991 meters) [Okamura and Ozawa,1995]. One of the key obstacles preventing a faster and wider use of SCC in Europe was the absence of suitable test methods to identify its three key fresh properties: filling ability, passing ability and resistance to segregation. This was hindering the increased use of SCC [European Union Growth,2005]. Experimental work The most important basic principle for flowing and unsegregable concretes including SCC is the use of the super plasticizer combined with a relatively high content of powder materials in term of Portland cement , mineral addition , ground filler and/or very fine sand. A partial replacement of Portland cement by fly ash was soon realized to be the most compromise in terms of rheological properties, resistance to segregations, strength level, and crack freedom. Some other alternative to fly ash , have been considered in the present paper, they are very fine sand and ground limestone. Two compacting concretes were manufactured using very fine sand (FSCC), and limestone(LSCC), in addition to the traditional concrete (TC). The following Tables (1,2,3) show the composition of each type of concrete. Tables (A-C)show the properties of materials that used in this research. Figure (1) shows the percentage of fine particles for traditional concrete and self compact concrete, it is clear that the percentage of fine particles of self compacting concrete is higher than that for traditional concrete, which represent one of most important criteria of SCC. Slump test for TC was made according to ASTM C143-99, and the slump flow for SCC was made using the cone of the slump test , by measuring the diameter of concrete circle after lifting the filled cone with concrete. Bleeding of concrete was measured using the test described by ASTMC232-99. Concretes were casted into Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٤٩ 15*15*15cm cub without any compacting or vibration for SCC ,and with compacting for TC. all concrete cubes were wet till the age of testing. Disussion of Results Table(4) describes the properties of fresh concrete for self-compacting concrete. Self compacting concrete with very fine sand shows slump flow of 650mm after 30 minute less than the self compacting concrete with limestone which shows slump flow of 700mm after 30minut, in addition the segregation for FSCC could be described as fair comparing to no or legible segregation for LSCC . Figure (2)shows the bleeding capacity as a function of the slump level fortraditional concrete (TC) with a cement factor 400 kg/m3 in the absence of superplasticizer. The slump was increased by increased the amount of mixing water. When the slump is over 175 mm the bleeding increases too much and this was the reason why ACI in 1973 did not recommend slump higher than 175 mm . With the advent of super plasticizers, SCC concretes with slump flow up to 700 mm were manufactured with no or negligible bleeding provided that an adequate cement factor was used. The self compacting concrete (FSCC),and (LSCC)show no or legible bleeding as shown Figure (3). Figure (4) describe the compressive strength of (TC) ,(FSCC) and(LSCC) it is clear that the compressive strength of self compacting concrete was higher than the compressive strength of traditional concrete . that because using super plasticizer which led to reduce the mixing water ,the reduction of water lead to increase of the compressive strength. in addition the use of fine particles of (fine sand &limestone) led to reduce the voids in the mix and make it strong. in addition the compressive strength of( LSCC) was higher than the strength of (FSCC), that because, the fine particles of limestone are more effective than the particles of very fine sand. Conclusions 1. The results obtained in the present paper show the extra-ordinary properties which can be obtained by using the innovative concretes recently developed in the field of SCC. SCC appears to be very successful because it is easy to place in a safe way independent of the quality and reliability of the workmanship available today on the jobsites. Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥٠ 2. The high-strength SCC studied in this paper can be considered as particularly suitable in the field of Civil Engineering. 3. The combined use of Cement type I (400kg/m3), super plasticizer (1.1-1.5%), Limestone or very fine sand (130-160 kg/m3), and aggregate with a maximum size of 20 mm allow the manufacture of self-compacting concretes suitable for concrete structures. 4. the most important progress achievable in the future for SCC technology depends on the availability and use of some new ingredients such as: a) Powder materials including (recycled aggregate from demolished concrete , etc.). b) more effective super plasticizers those based on acrylic polymers. c) viscosity modifying admixtures based on organic polymers and ultra fine amorphous colloidal silica. References 1- Final Report September ,2005 ,”Measurement of properties of fresh self- compacting concrete “,European Union Growth Contract No. G6RD-CT-2001- 0580. 2- M.Collepardi, 2002 ,"Self copacting concrete : what is new"pp.3-8. 3- Surendra P. Shah ,2005, “proceedings of the Fourth International RILEM Symposium on Self- Compacting Concrete” . 4- V. Corinaldesi, G. Orlandi, G. Moriconi,2002, «Self-Compacting Concrete Incorporating Recycled Aggregate», Proceedings of the International Conference "Challenges in Concrete Construction - Innovations and Developments in Concrete Materials and Construction", Dundee,Scotland, UK, 9-11 September 2002, pp. 455 – 464. 5- Okamura, H. and Ouchi, M., 1999, "Self-compacting concrete-development, Present and future", Proceedings of the First International RILEM symposium on Self-Compacting Concrete, pp. 3-14. Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥١ 6- Okamura, H. and Ozawa,K.,1995, "Mix Design for Self Compacting Concrete", Concrete library of JSCE, No.25, June, 1995, pp107-120.pp.4-16 7- Frank Dehn, Kluse, H., and Driek, W.,2002," Self compacting concrete time development of the material properties and bond behavior" pp.10-17 8- ASTM stander C143 “ test method of slump test”1999. 9- ASTM stander C232 “standard test methods for bleeding of concrete”1999. table (1) the composition of traditional concrete (TC) Ingredients kg/m3 Ordinary Portland cement type I 400 Coarse aggregate 20-5mm 1040 Fine aggregate Zone 2 760 Water 180 w/c 0.45 table (2) the composition of self compacting concrete with very fine sand(FSCC): Ingredients kg/m3 Ordinary Portland cement type I 400 Coarse aggregate 9.5-20mm 875 Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥٢ 5-9.5mm 440 Fine sand Zone 2 Very fine sand 0.075-0.6mm 430 100 limestone - Water 180 w/c 0.45 Super plasticizer 9.6 table (3) the composition of self compacting concrete with limestone (LSCC): Properties FSCC LSCC Specific mass kg/m3 2350 2400 Slump flow mm after: 0 min. 30 min. 60min. 680 650 620 740 700 680 Concrete aspect (segregation) Cohesive (fair) Cohesive (no) table (4) the fresh concrete properties of self compacting concrete Ingredients kg/m3 Ordinary Portland cement type I 400 Coarse aggregate 9.5-20mm 5-9.5mm 875 440 Fine aggregate Zone 2 Limestone 0.15-0.6mm 430 180 Water 180 w/c 0.45 Super plasticizer 8.6 table (a) chemical analysis of cement Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥٣ table (b) physical properties of cement Oxides Content % CaO SiO2 MgO Fe2O3 Al2O3 SO3 L.O.I 61.5 19.6 2.78 3.9 5.52 2.01 2.95 Compounds C3S 54.34 C2S 15.00 C3A 8.2 C4AF 11.55 Properties Results IOS No.5/1984 Fineness(Blaine)m2/kg 235 >230 Initial setting time 1:55 >0:45 min. Final setting time 4:00 <10:00 hours Compressive strength 3days 19.92 >15 N/mm2 Compressive strength 7 days 26.4 >23 N/mm2 Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥٤ table (c) the properties of aggregate and limestone properties Coarse aggregate sand limestone Specific gravity 2.63 2.53 2.69 SO3% 0.09 0.19 - Bulk density kg/m3 1637 1590 1700 Fineness modulus 2.86 - - absorption 0.6 0.9 0.8 figure (1) particle size distribution of the aggregate in SSC and TC. Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥٥ figure (2) bleeding capacity*104. as a function of slump for traditional concrete. figure (3) bleeding capacity *104 as a function of slump for self compacting concrete. Al-Qadisiya Journal For Engineering Sciences Vol. 2 No.4 Year 2009 ٧٥٦ figure (4) development of compressive strength with time for traditional concrete(TC) and for self compacting concrete with very fine sand(FSCC) and with limestone(LSCC).