Outline
- Abstract
- Keywords
- 1. Introduction
- 2. Experimental
- 3. Results
- 4. Discussion
- 5. Conclusion
- Acknowledgements
- References
رئوس مطالب
- چکیده
- کلیدواژه ها
- 1.مقدمه
- 2. آزمایش
- 3. نتایج
- 4. بحث
- 4. نتیجه گیری
Abstract
The addition of steel waste in the form of slags and dust to cement is beneficial to the environment because waste can be immobilized, and thus, decreasing the waters contamination. In this paper, paste and mortar-based Portland cement samples with up to 70.0 wt% of steel dust were investigated. Since it is known that for one ton of Portland cement fabricated 900 kg of CO2 are emitted to the environment, the addition of steel waste to cement is very beneficial. Moreover, since steel dust reduces the amount of needed cement in concrete, it reduces the final cost of concrete significantly. Additionally, the manufacturing processing was conducted entirely at room temperature; therefore, the negative impact of cement in the environment is reduced.
Scanning electron microscopy and X-ray diffraction characterization were conducted in order to investigate the microstructure of the samples. In addition, compression, density, and flow table tests were done over all samples. Thermo-gravimetric tests were performed to analyze the waste thermal stability. The effect of the potential hazardous components of this waste in water was analyzed through leachability tests. For all samples, compressive strength ranged from 73 to 2.5 MPa. The lowest strength value corresponded to 70 wt% of waste. Results show a solution for using this waste as admixture in cements and concrete, and therefore as a method for reducing cement paste in buildings and infrastructure.
Keywords: Cement paste - Ceramic powders - Composite - Mortar - Portland cement - Steel dustConclusions
Portland cement-steel dust waste composites were fabricated in this research. Up to 80 wt% over the total amount of powders were added and mixed mechanically. The lowest compressive strength found was 7.1 MPa corresponding to the sample with 70 wt% of steel dust. Even this value is competitive for many applications involving infrastructure and building materials such as decorative and other non structural parts. Results shows adding this slag to cement reduces the negative effect of slag in environment and reduces the cement binding in cement- and concretebased products.
Considering the data of CO2 produced by the fabricated Portland cement, samples fabricated in this research are up to 70.0 wt% of steel dust, which can reduce up to 630 kg of CO2 emitted to air per ton of fabricated cement. Moreover, since this steel waste reduces the amount of cement needed in concrete, it reduces the final cost of concrete significantly.
Although it is clear that samples with less waste had better strength, due to the complex multiphase materials found in the sample, it is necessary to conduct more research particularly in the hydration mechanisms. Leaching results over the water used for curing tests showed hazardous materials were all below the maximum permitted limits.