**2. Research plan**

#### **2.1 Material**

The aggregate was quarried from I-Lan River, Northern Taiwan, and consisted of large amounts of elongate slate and fragile particles. The cement and superplasticizer (SP) used corresponded to ASTM C150 type I Portland cement and ASTM C494 type F high range water reducing agent (HWRA), respectively. A naphthalene lingo-sulfonate base was used for promoting the flow ability of SCC; the specific gravity was 1.18; ph, 6.93 and chloride ion content, less than 50 ppm. As a by-product of the carbon steel manufacturing process, while the carbon steel settles in the smelter (since its density is high), impurities remain on top. The carbon steel is then transported to a water basin maintained at a low temperature for solidification. The end product (CSS) is a hard solid material that is then sent to a crusher for further processing. The CSS is powdered to pass through sieve No. 4 (4.76 mm). Subsequently, it is re-ground for 3 h at a speed of 60 rpm to pass through sieve No. 200 (75 μm). In this study, type I Portland cement has been used. Class F fly ash and BF slag were obtained from Taiwan Power Company and China Steel Corporation, respectively. The SP was Glenium 51 obtained from Taiwan Durusle Company, Taiwan. In Table 1, the specific gravities of Portland cement and CSS are listed as 3.14 and 2.67, respectively; further, CSS powder and Portland cement (type I) have specific surface areas of 2504 cm2/g and 3622 cm2/g, respectively. Hence, CSS has the least fineness, which is characteristic of materials with low surface areas. As shown in Table 2, CSS is highly alkaline, with a pH of 11.50, an absorption capacity (SSD) of 7.60%, fineness modulus (FM) of 1.76 according to ASTM C136, and dry loose density of 1266 kg/m3 according to ASTM C29. Figure 1 shows the relationships of CSS with BFS and Portland cement; the percentage of the main composition (SiO2 and CaO) of CSS lies between that of BFS and Portland cement.

Hwang CL,2004.Yu-Chu Peng,2009.]. Hence, CSS can be considered for use as a pozzolanic

Rather than use CSS for backfill soil or as material to be retained in the plant, steel slag can be regarded as a low-quality clinker and can be used to partially substitute the clinker of composite Portland cement [Wu X, Zhu H, Hou X, Li H,1999.Sakuraya T,1999.]. In Japan and other industrialized countries, steel slag has already been applied for use in civil engineering applications such as road base construction and soil stabilization [Geiser J.,1999. Roy DM, Idorn GM.,1982.]. In Germany, anbout 17.1% of steel slag is used for highway construction, 5.4% is recycled, and 40.5% is used in agricultural fertilizer production [Luxán MP, Sotolongo R, Dorrego F, Herrero E.2000. Monshi A, Asgarani MK,1999. Mihashi H, Yan X, Arikawa S.,1995. Hogan FJ, Meusel JW.,1981. ACI Committee 211.,1993.]. The mineralogical composition of steel slag is as follows: anhydrous calcium silicates and silicoaluminates; gehlenite, larnite and bredigite; magnetite and magnesioferrite and manganese oxides [Esfahani M. Reza,Kianoush M. Reza,2005. Hwang Soo-Duck,2008. Koehler Eric P. ,Fowler David W.,2008.]. Thus, some researchers have tested the effects of mixed iron slag (36%~45%), steel slag (6%~22%) and limestone (40%~64%) on the setting time of cement paste and the compressive strength at 3, 7 and 28 days [Schindler Anton K.,Barnes Robert W.,Roberts James B.,2007. Whitcomb Brent L., Kiousis Panos D.,2008.]. Nevertheless, other than documenting the chemical composition of CSS, there are few

The aggregate was quarried from I-Lan River, Northern Taiwan, and consisted of large amounts of elongate slate and fragile particles. The cement and superplasticizer (SP) used corresponded to ASTM C150 type I Portland cement and ASTM C494 type F high range water reducing agent (HWRA), respectively. A naphthalene lingo-sulfonate base was used for promoting the flow ability of SCC; the specific gravity was 1.18; ph, 6.93 and chloride ion content, less than 50 ppm. As a by-product of the carbon steel manufacturing process, while the carbon steel settles in the smelter (since its density is high), impurities remain on top. The carbon steel is then transported to a water basin maintained at a low temperature for solidification. The end product (CSS) is a hard solid material that is then sent to a crusher for further processing. The CSS is powdered to pass through sieve No. 4 (4.76 mm). Subsequently, it is re-ground for 3 h at a speed of 60 rpm to pass through sieve No. 200 (75 μm). In this study, type I Portland cement has been used. Class F fly ash and BF slag were obtained from Taiwan Power Company and China Steel Corporation, respectively. The SP was Glenium 51 obtained from Taiwan Durusle Company, Taiwan. In Table 1, the specific gravities of Portland cement and CSS are listed as 3.14 and 2.67, respectively; further, CSS powder and Portland cement (type I) have specific surface areas of 2504 cm2/g and 3622 cm2/g, respectively. Hence, CSS has the least fineness, which is characteristic of materials with low surface areas. As shown in Table 2, CSS is highly alkaline, with a pH of 11.50, an absorption capacity (SSD) of 7.60%, fineness modulus (FM) of 1.76 according to ASTM C136, and dry loose density of 1266 kg/m3 according to ASTM C29. Figure 1 shows the relationships of CSS with BFS and Portland cement; the percentage of the main composition

admixture to partially replace Portland cement in a concrete mixture.

studies on the pozzolanic reactions after the addition of CSS.

(SiO2 and CaO) of CSS lies between that of BFS and Portland cement.

**2. Research plan** 

**2.1 Material** 


Table 1. Physical properties and chemical composition of OPC and CSS.

Fig. 1. Comparison of compositions of CSS, BFS and Portland cement.

Carbon Steel Slag as Cementitious Material for Self-Consolidating Concrete 327

Fig. 3. Comparison between the OPC and CSC with respect to penetration resistance of

Fig. 2. Slump vs. various w/cm ratios of concrete.

concrete.

### **2.2 Mixture design**

In order to obtain high-strength SCC with lower water content (160 kg/m3), in this study, w/cm ratios (water/(cement+CSS)) of 0.28, 0.32 and 0.40 were selected. Further, large amounts of SP were added to achieve better flow behaviour. CSS powder was used to replace the 5.0%, 7.5% and 10% weights of Portland cement. Mixtures with three different w/cm ratios were prepared for ordinary plain concrete (OPC) and carbon steel slag concrete (CSC), as shown in Table 2; designated as OPC28, OPC32 and OPC40 and CSC28, CSC32 and CSC40, respectively﹝Whitcomb Brent L., Kiousis Panos D.,2009. Kwan Albert K. H.,Ng, Ivan Y. T.,2008.﹞.


a w/c ratio = water/cement

b w/cm ratio = water/(cement + CSS)

c SP = Superplasticizer

Table 2. Mixture proportion of SCC.
