Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 625 SULFATES EFFECT IN FINE AGGREGATE ON SELF COMPACTING CONCRETE PROPERTIES BY USING RISE HUSK ASH Received 12 July 2015 Accepted 30 August 2015 ABSTRACT One of the important problems in fine aggregate is the contaminated with interior sulfates in manufacturing concrete in Iraq. Within standard specifications a difficult to obtain of well-graded fine aggregate with sulfates content is existed. The present research is devoted to enhancement of some properties of self-compacting concrete with fine aggregate contains internal sulfates by partial replacement of gypsum to fine aggregate by weight. This study is bifurcate of self- compacting concrete they are: first category is incorporating powder of limestone (LSP) in self- compacting concrete and the second one is incorporating 10% rise husk ash (RHA) plus powder of limestone (LSP). The investigated scales of fine aggregate with sulfates contents were ( 0.37%, 0.5%, 1.0%, and 1.5%) which is corresponding replacement by weight of cement equal of (3.74%, 3.99%, 4.96% and 5.93%) for mixes contained limestone powder and of (3.76%, 4.01%,4.98% and 5.96%) for mixes contains rise husk ash plus powder of limestone. Experimental program of this study is bifurcate; first one is using superplasticizers and fillers to produce self-compacting concrete then determine the workability. Second one is to evaluate the mechanical properties such as splitting tensile strength and compressive strength. It was noticed that, the exemplary content of gypsum was by weight of cement for all mixes was 0.5%. While increase in compressive strength in a range between 5.9% and 10.1%, and in tensile strength in a range between 1.2% and 8.5% for mixes of self-compacting concrete with limestone powder plus rise husk ash instead of limestone powder. باستخدامالكبريتية في الركام الناعم على خواص الخرسانة ذاتية الرص حاألمالتأثير رماد قشور الرز Dr. Nabeel Hasen Ali Al-Salim Lecturer in Civil Engineering, University of Babylon dr_nabeelalsalim@yahoo.com Haider Mohammed Majeed Asst. Prof. in Civil Engineering, University of Babylon hdr_eng@yahoo.com Dr. Haider K. Ammash Asst. Prof. in Civil Engineering, University of Al-Qadisyia E-mail:amashhk@gmail.com كاظم عماش رد. حيد أستاذ مساعد المدنيةقسم الهندسة كلية الهندسة جامعة القادسية حيدر مجيد البغدادي أستاذ مساعد قسم الهندسة المدنية كلية الهندسة جامعة بابل حسن علي السالم لد. نبي مدرس قسم الهندسة المدنية كلية الهندسة جامعة بابل Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 625 الخالصة من القياسية المواصفات ضمن. العراق في الخرسانة تصنيع في الداخلية الكبريتاتب تلوثه وه الناعم الركام في الهامة المشاكل من واحدة الخرسانة خواص بعض تعزيز إلى البحث هذا ويخصص. الكبريتات محتوى وجود مع الناعم الركام جيد تصنيف على الحصول الصعب الدراسة هذه. ايوزن الركام الناعم بالجبس استبداال من جزء استبدال طريق عن الداخلية الكبريتات على الحاوي الناعم الركام مع ذاتية الرص وثانية ذاتية الرص الخرسانة في( LSP) الجيري الحجر مسحوق دمج هي األولى الفئة: هم ذاتية الرص تنقسم الى صنفين الخرسانة من الناعم لركامل نتائج االستكشاف كانت(. LSP) الجيري الحجر مسحوق إلى باإلضافة ،(RHA) من رماد قشور الرز٪ 01 دمج وه االخرىو و٪ 3335 ،٪333. ،٪353.) يساوي الى االسمنتمن وزن استبدال يقابلها والتي٪( 036و ،٪031 ،٪136 ،٪13.5) الكبريتات الحاوي على رماد قشور الرز الحاوية علىللخلطات ٪( 6335 و٪ 3334 ،٪3310 ،٪355.)و الجيري الحجر مسحوق للخلطات الحاوية على٪( .633 إلنتاج المادة المالئةو الملدنات استخدام هو قسم أول ؛ينقسم الى قسمين الدراسة هذه من الجانب العملي. الجيري الحجر مسحوق الى باالضافة . نضغاطاال وقوة لشد االنشطاريمقاومة ا مثل الميكانيكية الخواص لتقييم هو القسم االخرو. التشغيل قابلية تحديد ثم ذاتية الرص الخرسانة تقع ما بين االنضغاط قوة في الزيادة بينما٪. 136 كان الخلطات لجميع االسمنت من وزنا الجبس من القيمة المثلى تكان ،مالحظة ما يلي وقد رماد إلى باإلضافة الجيري الحجر مسحوق مع ذاتية الرص-الخرسانية للخلطات٪ 436 و٪ 032 تقع ما بين الشد قوةبينما ،٪0130 و٪ 633 .الجيري الحجر مسحوق من بدال قشور الرز ذاتية الرص، رماد قشور الرز، االمالح الكبريتية، الديمومة، الركام الناعم، مقاومة االنضغاط، مقاومة ةخرسانالمفاتيح الداللية: الشد 1. INTRODUCTION During the last decade, self–compacting concrete (SCC) is outstay in advances concrete technology. The SCC is developed in Japan since the last of 1980s, which is meanwhile spread all over the world with a continuously increasing of applications.( Holschemacher and Klug, 2002). Self-compacting concrete (SCC) was developed to respond to the need for concrete which can improve durability while eliminating the need for compaction and vibration work. SCC can compact itself into complicated formwork and congested structural elements under its own weight without the need for mechanical vibration. It needs to be both highly deformable and resistant to segregation and bleeding (Okamura and Ouchi, 1999). Because of highly flow-able nature of self-compacting concrete, care is required to ensure adequate stability, passing ability and excellent filling ability (Sonebi and Walraven , 2007) To achieve this ability, ensuring suitable rheological fresh concrete properties of like adequate plastic viscosity with a low yield stress. To attain high flow-ability for fresh concrete water to binder attribution could be to increase in a simple manner. Increasing the water to binder ratio alone; however, might concrete to be less durability and lead to segregation. Thus, mineral and chemical admixtures, e.g., pozzolans, limestone powder, super-plasticizer, and viscosity-modifying admixture (VMA), need to be added to the mix for successfully develop SCC and to prevent segregation and enhance the workability of SCC (Suksawang , Nassif, and Najm, 2006). Sulfates cause concrete or mortar deterioration when it exists in excessive amount. This phenomenon is called sulfate attack. The sulfate reacting with Ca(OH)2 with hydrate of calcium aluminates (H-C-A). The volume of gypsum and calcium sulphoaluminate products reactions is a considerably great in a comparison with the compounds they replace; therefore, expansion and disruption of the concrete will occur in the reaction with the sulfates. Sulfate in fine aggregate is a major problem encountered in the Middle and Southern part of Iraq. Most of the sulfate salts in fine aggregate are composed of calcium, magnesium, potassium and sodium sulfates. Calcium sulfate is the most predominant salt present in Iraqi fine aggregate. It is usually finding in fine aggregate as Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 624 gypsum. About 95% of sulfates in fine aggregate are in the form of calcium sulfates because of the low solubility of this type of sulfate (Al-Samerai 1977 ). Sulfates may come either from raw materials and or from gypsum added to cement at grinding stage. (Al-Qaisi,1989) Stated that the activity of gypsum is dependent on its fineness. (Al-Rawi, Ali, Shallal and Al-Salihi, 1997) studied the effective sulfate content in concrete ingredients, they pointed out that the effect of SO3 existing in cement on compressive strength of concrete is about two times more that in fine aggregate and effect of the latter is about two times more that in coarse aggregate. They attributed this to the fine particle size distribution of cement compared with fine aggregate and coarse aggregate. In a later study by (Al-Rawi, 2000), to develop the concept of effective sulfate content, he found that the effectiveness of sulfates increased with increased fineness of fine aggregate. He suggested a formula to account for the effectiveness of sulfates in fine aggregate depending on its fineness modulus. He showed also that the same formula is applicable. The sulfate content in fine aggregate contains sulfate higher than the acceptable limits in most of the fine aggregate in Middle East countries (Al-Kadhimi and Hamid, 1983). (Al-Ameeri and Issa,2013) results show that the fresh properties such as decreased workability of self-compacting concrete is passively influenced from sulfate, also the hardened properties. Furthermore, they found that the optimum SO3 content to give little tendency to expanding and maximum strength is up to 5% (by weight of cement) which is acceptable limits more than Iraqi specifications. In addition, they noticed a considerable reduction of self-compacting concrete mechanical properties, and increment in expansion of concrete after increase the optimum value of sulfates content in concrete.(Al- Rawi,1997) investigated the effect of the gypsum content of cement on several engineering properties of concrete cured by accelerated and normal methods. He stated that increased gypsum content results in a significant decrease in the slump of concrete and that there is an optimum gypsum content, considerably higher for accelerated cured concrete than for normally cured concrete, at which maximum strength is obtained. The optimum gypsum content under accelerate curing conditions may be used without risk of reduction in the durability of concrete caused by excessive, delayed expansion. (Al- Rawi, and Latif, 1998), suggested a new test called "Compatibility test" to investigate the possibility of using sands with relatively high (SO3) contents with suitable cement without deleterious effect on concrete. The work was carried out on seven cements, three ordinary Portland cement, three sulfate-resisting cements and white cement. The sand used had SO3 contents between 0.18% and 1.5% and the mix was designed to give 30 MPa compressive strength at 28 days. The results show that the SO3 content in sand gives the maximum concrete strength which differs from one cement to the other ranging from (0.18% to 1.5%) depending on the chemical composition and fineness of cement. (Alwash, 2005) found the percentage in compressive strength of the mix with OPC and sand of zone 2 which contains sulfate of 1.5% by weight of it, compared with the reduction in strength of the mix with OPC and sand of zone 4 which contains sulfate of 1.5% by weight of it. At ages 7, 28 and 56 days the reduction was (30.86%-37.7%), (10.47%-17.9%) and (2.29%-8.16%) for air curing and (23.6%-28.4%), (7.7%-13.4%) and (5.8%-5.5%) for moist curing. The influence of sulfates on elastic modulus and indirect tensile strength was found to be somewhat likely to that influence on compressive strength. (Hussain, 2008) investigated some mechanical properties of self-compacting concrete and effect of internal sulfates in fine aggregate on it with several filler types of such as powder of limestone, pigment and hydrated lime. The mechanical properties were flexural strength, modulus of elasticity, compressive strength, the ultrasonic pulse velocity, indirect tensile strength and schmidt Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 623 rebound hammer tests. He found the optimum gypsum content at which the strength is maximum . Further increase in SO3 content beyond the optimum causes a decrease in strength and nondestructive tests. (Kawkab &elt, 2008) used 8% partial replacement by weight of cement rise husk ash, the results showed considerable increase in mechanical properties at all ages of curing simulated with the original concrete. (Alwash, 2013) noticed in his experimental results that elastic modulus and strength of SCC at age after 60 days improved by adding rice husk ash. The optimum strength was at 15% replacement. Also, a reduction in water absorption and increase the ultrasonic pulse velocity was noticed using rice husk ash. 2. EXPERIMENTAL PROGRAM The research is devoted to enhancement of some properties of self-compacting concrete with fine aggregate contains internal sulfates by partial replacement of gypsum to fine aggregate by weight. The study is bifurcate of self-compacting concrete they are: first category is incorporating powder of limestone (LSP) in self-compacting concrete and second one is incorporating 10% rise husk ash (RHA) plus powder of limestone (LSP). Four scales of SO3 contents in fine aggregate were investigated; these scales were 0.37%, 0.5%, 1.0% and 1.5% by weight of sand. In order to view the differences in behavior during the fresh state as well as the hardened state some of tests were performed. The slump flow, V-funnels, sieve segregation and L-box tests were performed on concrete in the fresh state. The tests for splitting tensile strength and compressive strength were carried out on concrete specimens at ages (28, 56 and 90 days). The details of each concrete mix were listed in Table 1. 2.1 MATERIALS 2.1.1 Cement The ordinary Portland cement (named Tasluja Bazian) is used. The cement was tested and compared according to (IQS No.5 /1984). The chemical and physical tests were conducted in Construction Materials Laboratory of Babylon University. 2.1.2 Fine Aggregate (Sand) Al-Akhaider natural fine aggregate with fineness modulus (2.64) was used throughout this work. Results indicate that the fine aggregate grading, physical properties and the sulfate contents are within the requirements of the Iraqi specification limits (IQS No.45 /1984). 2.1.3 Coarse Aggregate (Gravel) Rounded coarse aggregate of passing sieve size 10 mm from AL- Nibaee quarry is used. The coarse aggregate was washed and then stored in air to dry. The grading of this aggregate which conforms to Iraqi Specifications limits (IQS No.45/1984). The specific gravity and sulfate content of coarse aggregate are within the requirements of the Iraqi specifications limits (IQS No.45 /1984). 2.1.4 Water For both mixing and curing all specimens ordinary tap water is used. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.1 2.1.5 Superplasticizer A chemical admixture based on modified polycarboxylic ether, which was known commercially (Glenium 51) was used in producing SCC as a superplasticizer admixture. It was complied with (ASTM C494-05 Type F). 2.1.6 Limestone Powder (LSP) Limestone powder is a white ground material from limestone that found in different regions in Iraq, and usually used in the construction processes. Limestone powder that has been brought from local market is used to increase the amount of powder (cement + filler), the fraction less than 0.125mm will be of most benefit. This filler conforms the (BS 7979) . The chemical analysis of LSP was listed in Table 2. 2.1.7 Gypsum The gypsum was added to the fine aggregate to obtain the required SO3 content. The added gypsum is natural gypsum rock (brought from Kufa cement factory). It was crushed and grounded to obtain nearly the same gradation set of fine aggregate used in the mix. This gypsum was using as a partial replacement by weight of fine aggregate with limited percentages. The quantity of natural gypsum was calculated and added to the fine aggregate according to the following equation(Al-Kadhimi and Hamid, 1983). W=(R – M) S / N (2-1) where: W= the weight of natural gypsum needed to be added to fine aggregate. R= the percentage of SO3 % desired in fine aggregate. S = the weight of fine aggregate in mix. M = the actual SO3 in fine aggregate (0.37 %). N= the percentage of SO3 % in the used natural gypsum. 2.1.8 Rise Husk Ash (RHA) Prepared of rice husk ash was by burning the husk in a controlled temperature furnace in order to get a pozzolanic material rich in amorphous silica and minimum amount of unburned carbon. Generally, the optimum burning condition was 500 o C for 2 hours (AL-Khalaf and Yousif, 1984). A grinding mill effected the grinding of ash for a period of 15 hours for each 0.5 kg of the ash. The fineness was determining by Blaine air permeability method in accordance with (ASTM C204-84). The fineness modulus and specific gravity were 1.45 and 1.85, respectively. The Chemical properties of rise husk ash (RHA) were listed in Table 3. 2.2 MIXING PROCEDURE In order to obtain the desired level of SO3 in the sample, first adding suitable amount of gypsum to the fine aggregate then fine aggregate and gypsum were mixed until a homogeneous mix is obtained. Rise husk ash (RHA) powder was mixed with the quantity of cement with the aid of Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.0 trowels, until the RHA particles were thoroughly dispersed between cement particles. Mixing procedure is important to obtain the required workability and homogeneity of the concrete mix. Concrete was mixed in drum laboratory mixer, with a capacity of 0.05m 3 . Before starting to mix, it is necessary to keep the mixer clean, moist and free from previous mixes. The procedure used for mixing the batches was as follows (Emborg ,2000): 1. Adding the fine aggregate to the mixer with 1/3water, and mixing for 1minute. 2. Adding the powder (cement+filler) with another 1/3 mixing water, and mixing for 1 minute. 3. After that, the coarse aggregate was added with the last 1/3mixing water and one third of superplasticizer, and mixing for 1.5 minute then the mixture is left for 1.5 minute for rest. 4. Then, the remaining of superplasticize (two third) is added and mixed for 1.5 minute. The SCC mix Proportions were summarized in Table 4. 2.3 TEST METHODS FOR FRESH (SCC) The fresh properties of plain SCC were tested by the procedures of (European Guidelines for self- compacting concrete) (Efnarc, 2005). SCC was defined by its behavior when it is in the fresh state, and it is determined whether concrete meets certain requirements, while flowability is an essential property in qualifying concrete as SCC or not. The slump flow, L-box, V-funnel, sieve segregation test and V-Funnel at T5 minutes were all used for all mixes of this study. 2.3.1 Slump Flow and T50cm Tests The most widely used method for evaluating concrete consistency and filling ability in the laboratory and at construction sites is the slump flow test and can indicate segregation resistance of SCC to an experienced user. Slump flow with Abrams cone was used to investigate flowing ability of fresh concrete. The slump spread values and T500 for the produced mixes listed in Table 5. 2.3.2 L-Box Test The passing ability of self-compacting concrete is measures by the L-box test. Originally developed in Japan for underwater concrete. Table 5 shows the value of L- Box (H1/H2) which represents the blocking ratio and the value of T400 represents the time of concrete to reach 400 mm flow. 2.3.3 V-Funnel Test And V-Funnel at T5 Minutes Tests To evaluate the material segregation resistance and to measure the filling ability (flowability) of SCC the V-funnel can be used. Table (5) shows test results of V-funnel. No blocking or segregation behavior observed in all mixes, and these results are within the limits pointed out in the literatures. 2.3.4 Sieve Segregation Resistance Test To assess the resistance of (SCC) to segregation sieve segregation test is used. Table (5) shows the value of segregation resistance results test of (SCC) mixes. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.2 2.4 TESTING OF HARDENING (SCC) 2.4.1 Compressive Strength According to Iraqi specification (IQS No.348-1992), compressive strength test was carried out on 150 mm cubes by using a hydraulic compression machine with a capacity of 2000 kN. For each test average of three cubes was adopted. 2.4.2 Splitting Tensile Strength According to the procedure outlined in Iraqi specification (IQS No.283-1995), indirect tensile strength was carried out. Cylindrical concrete specimens (100x200 mm) were used. In each test average of three specimens is taken. 3. RESULTS AND DISCUSSIONS 3.1 Compressive Strength The compressive strength test results of the concrete specimens were tested at ages (28, 56 and 90 days), three cubes are tested at each age to compressive strength of self-compacting concrete with various percentages of gypsum content in fine aggregate are shown in Table ( 6) and Figs. (1) and ( 2) .It can be seen that for all mixes, there is an optimum SO3 content at which the compressive strength is maximum, beyond which content the compressive strength has decreased. The present data indicates that the optimum SO3 content for these mixes is about (0.5) % (by weight of sand) and it is equal to 3.99 % (by weight of cement) for mixes that contain limestone powder filler and it is equal to 4.01% (by weight of cement) for mixes which contain limestone powder filler and rise husk ash (RHA). From the results of compressive strength shown in Table 6, and Fig. 1 and 2 it can be noticed that: 1. When SO3 content in fine aggregate increases from (0.37 to 0.5%), this leads to an enhancement in compressive strength of concrete cubes in the range (5.9, 7, and 8.7%) for DL1 at ages (28, 56 and 90) days respectively. 2. When SO3 content in fine aggregate increases from (0.37 to 1%), this leads to a diminution in compressive strength of concrete cubes in the range (5.4, 6.8 and 7.7) % for DL2 at ages (28, 56 and 90) days respectively. 3. When SO3 content in fine aggregate increases from (0.37 to 1.5%), this produce to a diminution in compressive strength of concrete cubes in the range (8.2, 8.8 and 9.9 %) for DL3 at ages (28, 56 and 90) days respectively. This was expected since several researchers as mention before, had referred to the presence of optimum gypsum content. The enhancement in compressive strength of the concrete can attribute to the ettringite formation, which was produced by a chemical reaction between SO3, C3A and water. It fills some of the voids inside the cement past and increases the strength. But more ettringite formation motives internal stresses and decreases the compressive strength (Neville, 1995) and (Al- Ameeri and Issa,2013). Also, results showed that the use of 10% rise husk ash (RHA) in self-compacting concrete was the best compared with other mixes that contain limestone powder (LSP) by improving compressive strength for all sulfates contents and for all ages as shown in Fig's below . Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.. Figs. (3) and (4) show the effect of rise husk ash (RHA) on compressive strength at ages 28 and 90 days with increment percentage as (24.6, 26.7, 29.9 and 27.1)% at 28 days and (28.5, 30.5, 30.9 and 30.9) at 90 days for levels of sulfates contents in fine aggregate ( 0.37, 0.5, 1.0, and 1.5)%. The results indicated that the (SCC) with (RHA+LSP) yielded the lowest compressive strength loss when compared (SCC) with (LSP), this can be attributed to the fact of the incorporation of (RHA) in SCC mix leads to minimizes the compressive strength loss compared to mixes without (RHA). This behavior because of pozzolanic effect of (RHA) which reacts with the calcium liberated (during the hydration of cement) and contributes to densification of the concrete matrix resulting in a considerable increase in strength and reduction in permeability. Also, the grain size and pore-size refinement process associated with pozzolanic reaction can effectively reduce the microcracking and strengthen the transition zone (Neville, 1995). 3.2 SPLITTING TENSILE STRENGTH Splitting tensile strength (indirect tensile strength) of self-compacting concrete results of the (28, 56 and 90 days) with various percentages of SO3 content in sand are presented in Table (7) and Figs.(5) and Fig.(6) for different mixes. It is clear that the effect of sulfates on the indirect tensile strength is somewhat similar to that on compressive strength. For all mixes, there is an optimum SO3% content at which the splitting tensile strength is maximum, beyond this content indirect tensile strength has decreased. From the results of splitting tensile strength shown in Figs. 5 and 6 it can be it can be noticed that: 1. When SO3 content in fine aggregate increases from (0.37% to 0.5%), this leads to enhance in indirect tensile strength of the concrete cylinders in value of (1.2., 4.5 and 6.4 %) for DL1 at ages (28, 56 and 90) days respectively. 2. When SO3 content bin fine aggregate increases from (0.37 to 1%), this leads to a decrease in indirect tensile strength of the concrete cylinders in the range (3.3, 3 and 2.7%) for DL2 at ages (28, 56 and 90) days respectively. 3. When SO3 content in fine aggregate increases from (0.37% to 1.5%), this leads to a decrease in indirect tensile strength of the concrete cylinders in value of (5.6, 5 and 4.8%) for DL3 at ages (28, 56 and 90) days respectively. These results agree with that obtained by (Alwash, 2005) and (Hussain, 2008). In addition Also, results showed that the use of 10% rise husk ash (RHA) in self-compacting concrete was the best compared with other mixes that contain limestone powder (LSP) by improving splitting tensile strength loss for all sulfates contents and for all ages as shown below :- 1. When SO3 in fine aggregate increases from (0.37% to 0.5%) this leads to an increase indirect tensile strength of the concrete cylinders in value of (4.7, 6.2, and 8.5%) for DLR1 at ages (28, 56 and 90) days respectively. 2. When SO3 in fine aggregate increases from (0.37 to 1%), this leads to a decrease indirect tensile strength of the concrete cylinders in value of (2.4, 2.6 and 2.1%) for DLR2 at ages (28, 56 and 90) days respectively. 3. When SO3 in fine aggregate increases from (0.37 to 1.5%) this leads to a increase indirect tensile strength of the concrete cylinders in value of (4.5, 4.0 and 3.8%) for DLR3 at ages (28, 56 and 90) days respectively. Figs. 7 and 8 show the effect of rise husk ash (RHA) on indirect tensile strength at ages 28 and 90 days with increment percentage as (25.3, 29.7, 26.5, and 26.8%) at 28 days and (25.0, 27.5, 25.7 and 26.3) at 90 days for levels of sulfates contents in fine aggregate ( 0.37, 0.5, 1.0, and 1.5%). Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.3 4. CONCLUSIONS The following conclusions can be noticed from the experimental work,- 1. With a constant superplasticizer dosage and water content, (SCC) mixes with (LSP) had a better a passing ability filling ability, and segregation resistance than (SCC) mixes with (RHA+LSP) in the fresh state. 2. There is an optimum gypsum content in which both indirect tensile strength and compressive strength are maximum, beyond this content the splitting tensile strength and compressive strength decrease. The optimum gypsum content for these mixes is about (0.5% by weight of fine aggregate) and it is equal to (3.99%) by weight of cement for mixes containing (LSP), while it is equal to (4.01% by weight of cement) for mixes containing (RHA+LSP). 3. The (SCC) which contain 10% (RHA) as a partial permutation by weight of cement in mixes contain (RHA+LSP) was found to be effective in reducing compressive strength and splitting tensile strength due to interior sulfates contents in fine aggregate beyond optimum gypsum contact as compared with mixes contain (LSP). REFERENCES [1] Holschemacher, K., and Klug, Y.,(2002) “A Database for the Evaluation of Hardened of SCC”, LACER No. 7, 2002, PP.123-134. 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[7] Al-Rawi, R.S., Ali, N.H., Shallal, A.R. and Al-Salihi, R.A., (1997) “Effective Sulfate Content in Concrete Ingredients", 4th Scientific and Engineering Conference, Baghdad,pp.18- 20. [8] Al-Rawi, R.S., (2000) “Some Problems in Concrete Manufacture in The Arab Homeland and Suggested Remedial Measures", Arab Conference of Construction Materials in Egypt , pp.669- 681. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.6 [9] Al-Kadhimi, T. K. and Hamid, F. A., ( 1983) “ Effect of Gypsum Present in Sand on the Properties of Concrete", BRC-Journal, Vol.2, No.2, , pp.17- 41. [10] Al Ameeri ,A and Issa ,R. H., “Effect of Sulfate on the Properties of Self Compacting Concrete Reinforced by Steel Fiber”, International Journal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 2, 2013, pp. 270 - 287, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. [11] Al- Rawi R.S.,(1997), “Gypsum Content of Cements Used in Concrete Cured by Accelerated Methods", Journal of Testing and Evaluation V.5, No.3, May, pp. 231-236. [12] Al- Rawi, R.S and Latif A., (1998) “ Compatibility of Sulphate Contents in Concrete Ingredients", Fourth Scientific Conference , College of Engineering of Baghdad University. [13] Alwash, J.J., (2005) “Effect of Sulfates in Fine Aggregate on drying Shrinkage Cracking in End Restrained Concrete Members" M.Sc. Thesis, University of Babylon, College Of Engineering [14] Hussain, T. H., (2008) “ Effect of Sulfates in Fine Aggregate on some Mechanical Properties of Self Compacting Concrete". M.Sc. Thesis, University of Babylon, College Of Engineering [15] Kawkab H. Al-Rawi , Mazin T. Al-Kuttan , Rawa'a A. Al-Niemey “Some Mechanical Properties Of Pumice Lightweight Aggregate Concrete Incorporating Rise Husk Ash” University of Technology,2008 [16] Alwash, J.J.,(2013)“Self Compacting Concrete Incorporating Rice Husk Ash And Metakaolin” Babylon University, College of Engineering, AL-Qadisiyia Journal For Engineering Sciences ,Vol. 6,No 2 . [17] Iraqi Specification, No.5/1984, “Portland cement” Central Organization for Standardization &Quality Control COSQC, Baghdad, 2001 [18] Iraqi Specification, No.45/1984, “Aggregates from natural sources for concrete and construction” Central Organization for Standardization &Quality Control COSQC, Baghdad, 2001. [19] American Society for Testing and Materials, ASTM C 494-05, “Standard Specification for Chemical Admixtures for Concrete “Annual Book of ASTM Standards, Vol. 04-02, 2005. [20] British Standards Institution ,BS 7979-01, Specification for limestone fines for use with Portland cement. [21] AL-Khalaf, M.N., and Yousif, H.A., "Use of rice husk ash in concrete", the international Journal of cement Composites and lightweight concrete, Vol.6, No.4, Nov, pp. 241-248,.1984. [22] ASTM C204-84, "Standard test method for fineness of Portland cement by air permeability apparatus", Annual Book of ASTM Standards, Vol. 04-02, pp.157-162,1989 [23] Emborg M., ,(2000) “ Mixing and Transport ", Brite EuRam, Task 8.1. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.5 [24] EFNARC, (2005), ”The European Guidelines for Self-Compacting Concrete Specification, Production and Use”. The European Federation of Specialist Construction Chemicals and Concrete Systems. [25] Iraqi Specification, No.348/1992, ”Determination of Compressive Strength of Concrete Cubes”, Central Organization for Standardization &Quality Control COSQC, Baghdad. [26] Iraqi Specification, No.283/1995, ”Splitting Tensile Strength of Concrete” , Central Organization for Standardization &Quality Control COSQC, Baghdad [27] Neville, A.M., (1995), “Properties of Concrete'', Five, and Final Edition, Wiley, New York and Longman, London, pp.844. Oxides of RHA Percentage Oxides of RHA Percentage SiO2 93 AL2O3 0.1 CaO 1.31 P2O3 0.56 MgO 1.7 CL 0.36 Mixes designation Types of filler Curing Time (days) SO3 content in sand (by weight of sand) % Total SO3 content (by weight of cement) % DL* 0 DL 1 DL 2 DL 3 Limestone Powder (LSP) 28, 56, 90 0.37 0.5 1.0 1.5 3.74 3.99 4.96 5.93 DLR *0 DLR 1 DLR 2 DLR 3 Limestone Powder plus rise husk ash (LSP+ RHA) 28, 56, 90 0.37 0.5 1.0 1.5 3.76 4.01 4.98 5.96 Oxide Content % Oxide Content % SiO2 1.34 MgO 0.13 Fe2O3 0.12 SO3 1.90 Al2O3 0.69 CaO 55.13 Table (1): Concrete mix designations Table(2): limestone powder chemical analysis Table(3) Rice husk ash chemical and physical properties[21]. Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.5 Table( 6): Effect of sulfate content in fine aggregate on compressive strength of SCC SO3 0.1 Fe2O3 0.31 K2O 3.77 MnO 0.2 Na2O 1.5 L.O.I 2.51 Materials Materials Content Limitation (Kg/m3) Cement (kg/m 3 ) 400 350-450 Fine aggregate (kg/m 3 ) 775 710-900 Coarse aggregate (kg/m 3 ) 820 750-920 Filler (kg/m 3 ) 100 50-150 (Water / powder) ratio 0.42 0.33-0.62 SP (Liter/100kg cement) 3 - Test Unit Mix Notation Typical range of Values DL DLR Slump-flow mm 740 680 600-800 T 50cm sec 3 3.5 2-5 V-funnel sec 6 7 6-12 V-funnel at T5 min. sec. 7 9 +3 sec, max. L-Box (H2/H1) 1 0.9 0.8-1.0 SR % 3 2 ≤ 15% Mix Notation SO3 content % by weight of fine aggregate Total SO3 content % by weight of cement Compressive strength (MPa) for Ages 28 (days) 56 (days) 90 (days) DL0 0.37 3.74 35.3 39.7 42.4 DL1 0.5 3.99 37.4 42.5 46.1 DL2 1.0 4.96 33.4 37 39.1 DL3 1.5 5.93 32.4 36.2 38.2 DLR0 0.37 3.76 44.0 50.1 54.5 DLR1 0.5 4.01 47.4 54.3 60.0 DLR2 1.0 4.98 43.4 47.5 51.2 DLR3 1.5 5.96 41.2 46.4 50.0 Table (4): Mix proportions Table (5) Results of Fresh Properties of SSC of all Mixes Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.4 Table(7) Effect of sulfate content in fine aggregate on splitting tensile strength of SCC Mix Notation SO3 content % by weight of fine aggregate Total SO3 content % by weight of cement Splitting tensile strength (MPa) for Ages 28 (days) 56 (days) 90 (days) DL0 0.37 3.74 3.36 3.58 3.76 DL1 0.5 3.99 3.40 3.74 4.0 DL2 1.0 4.96 3.25 3.47 3.66 DL3 1.5 5.93 3.17 3.4 3.58 DLR0 0.37 3.76 4.21 4.52 4.70 DLR1 0.5 4.01 4.41 4.80 5.1 DLR2 1.0 4.98 4.11 4.4 4.6 DLR3 1.5 5.96 4.02 4.34 4.52 0.0 0.5 1.0 1.5 2.0 SO3% in Fine Aggregate 30 35 40 45 50 C o m p re s s iv e S tr e n g th ( M P a ) SSC Mixes with LSP 28 Days 56 Days 90 Days 0.0 0.5 1.0 1.5 2.0 SO3 % in Fine Aggregate 35 40 45 50 55 60 65 70 C o m p re s s iv e S tr e n g th ( M P a ) SSC Mixes with LSP and HRM 28 Days 56 Days 90 Days Fig. 1: Relationship between Compressive Strength and SO3 content in fine aggregate at different age with limestone powder filler. Fig. 2: Relationship between Compressive Strength and SO3 content in fine aggregate at different age with limestone powder filler and rise husk ash (RHA). Al-Qadisiyah Journal For Engineering Sciences, Vol. 8……No. 4 ….2015 6.3 0.0 0.5 1.0 1.5 2.0 SO3% in Fine Aggregate 4.0 4.4 4.8 5.2 S p li tt in g T e n s il S tr e n g th ( M P a ) SSC Mixes with LSP and HRM 28 Days 56 Days 90 Days 0.0 0.5 1.0 1.5 2.0 SO3 in Fine Aggregate % 2.8 3.2 3.6 4.0 4.4 S p li tt in g T e n s il e S tr e n g th ( M P a ) SSC Mixes with LSP 28 Days 56 Days 90 Days Fig. 6: Relationship between splitting tensile strength and SO3 content in fine aggregate at different age with limestone powder filler and rise husk ash (RHA). Fig. 5: Relationship between splitting tensile strength and SO3 content in fine aggregate at different age with limestone powder filler.