Evaluation on the Surface Modification of Recycled Fine Aggregates in Aqueous H2SiF6 Solution
Source abstract
Abstract
Recycled aggregates (RAs) production techniques are essential for the material circulation society because RAs from demolished concrete waste can sustainably be reused as a concrete material. However, RAs can bring about several performance decreases when they are used for recycled aggregate concrete (RAC) because of the low qualities (i.e., high water-absorption rate and low density) caused by the attached hydrated cement paste on the RA surface. Therefore, both the production of high-quality RAs and the surface modification of RAs are significantly important for the extension of RAC utilization. This paper focuses on the surface modification of RFA to reduce the water absorption rate and increase density. Hydrofluorosilicic acid (H2SiF6), which is one of the by-products in phosphoric acid manufacture, is used herein for the surface modification of the RFA. The physical properties and mechanical performance of mortar using RFA were evaluated after RFA modification. Consequently, the proposed method is effective in reducing water absorption rate and increasing density of RFA. The density of RFAs was slightly increased by 0.5–2.6% after modification. On the other hand, the water absorption rate decreased by 4–18% after modification. The compressive strengths of mortar at 28 days ages showed 18.1 MPa with modified RFA and 16.2 MPa with RFA.
Source: openalex_inverted_index · Quality: baseline
Research context
OpenAlex topics: Recycled Aggregate Concrete Performance · Innovative concrete reinforcement materials · Concrete and Cement Materials Research
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (30)
Show source-provided references
1. Al-Bayati, H. K. A., Das, P. K., Tighe, S. L., & Baaj, H. (2016). Evaluation of various treatment methods for enhancing the physical and morphological properties of coarse recycled concrete aggregate. Construction and Building Materials, 112, 284–298.10.1016/j.conbuildmat.2016.02.176 ↗
2. AS. (1996). Particle density and water absorption of aggregates (AS 1141.6.2-1996). Sydney: Australian Standard.
3. ASTM International. (2006). Standard test method for time of setting of hydraulic cement by vicat needle; ASTM C 191. West Conshohocken: ASTM International.
4. ASTM International. (2012). Standard test method for density, relative density (specific gravity), and absorption of fine aggregate; ASTM C128-12. West Conshohocken: ASTM International.
5. ASTM International. (2013a). Standard test method for flow of hydraulic cement mortar; ASTM C1437-13. West Conshohocken: ASTM International.
6. ASTM International. (2013b). Standard test method for compressive strength of hydraulic cement mortars (using 2-in. or [50 mm] Cube Specimens); ASTM C109 M-13. West Conshohocken: ASTM International.
7. ASTM International. (2014). Standard specification for flow table for use in tests of hydraulic cement; ASTM C230/230 M-14. West Conshohocken: ASTM International.
8. Behera, M., Bhattacharyya, S. K., Minocha, A. K., Deoliya, R., & Maiti, S. (2014). Recycled aggregate from C&D waste & its use in concrete-a breakthrough towards sustainability in construction sector: A review. Construction and Building Materials, 68, 501–516.10.1016/j.conbuildmat.2014.07.003 ↗
9. BS 812: Part 2. (1994). Testing aggregates. Method for qualitative and quantitative petrographic examination of aggregates. London: BSI.
10. Chen, P., Wang, J., Wang, L., Xu, Y., Qian, X., & Ma, H. (2017). Producing vaterite by CO2 sequestration in the waste solution of chemical treatment of recycled concrete aggregates. Journal of Cleaner Production, 149, 735–742.10.1016/j.jclepro.2017.02.148 ↗
11. Choi, H. S., Kitagaki, R., & Noguchi, T. (2014). Effective recycling of surface modification aggregate using microwave heating. Journal of Advanced Concrete Technology, 12, 34–45.10.3151/jact.12.34 ↗
12. Construction standard CS3. (2013). Construction standard CS3: 2013-Aggregates for concrete, Civil engineering and development department of Hong Kong. http://www.cedd.gov.hk/eng/publications/standards_handbooks_cost/stan_cs3_2013.html .
13. DIN 4226–100. (2002). Aggregates for mortar and concrete–Part 100: Recycled aggregates. Berlin: Deutsches Institut für Normung.
14. Ismail, S., & Ramli, M. (2014). Influence of surface-treated coarse recycled concrete aggregate on compressive strength of concrete. International Journal of Civil, Environmental, Structural, Construction and Architectural Engineering, 8, 862–866.
15. JIS A 5021. (2005). Recycled aggregate for concrete-class H. Tokyo: Japan Concrete Institute.
16. JIS A 5022. (2007). Recycled concrete using recycled aggregate class M. Tokyo: Japan Concrete Institute.
17. JIS A 5023. (2007). Recycled concrete using recycled aggregate class L. Tokyo: Japan Concrete Institute.
18. Kim, J. O., Nam, J. H., Kim, D. S., & Lee, B. K. (2004). Changes in hydration and watertightness of cement containing two-component fluosilicate salt based chemical admixture. Journal of the Korean Ceramic Society, 41, 749–755.10.4191/KCERS.2004.41.10.749 ↗
19. Kong, D. Y., Lei, T., Zheng, J. J., Ma, C. C., & Jiang, J. (2010). Effect and mechanism of surface-coating pozzalanics materials around aggregate on properties and ITZ microstructure of recycled aggregate concrete. Construction and Building Materials, 24, 701–708.10.1016/j.conbuildmat.2009.10.038 ↗
20. KS F 2573. (1999). Recycled aggregate for concrete. Seoul: Korea Standard Association.
21. Noguchi, T., Park, W. J., & Kitagaki, R. (2015). Risk evaluation for recycled aggregate according to deleterious impurity content considering deconstruction scenarios and production methods. Resources, Conservation and Recycling, 104, 405–416.10.1016/j.resconrec.2015.08.002 ↗
22. Ondova, M., & Sicakova, A. (2016). Evaluation of the influence of specific surface treatments of RBA on a set of properties of concrete. Materials, 9, 156.10.3390/ma9030156 ↗
23. RILEM TC 121-DRG. (1994). Specifications for concrete with recycled aggregates. Materials and Structures, 27, 557–559.10.1007/BF02473217 ↗
24. Ryou, J. S., & Lee, Y. S. (2014). Characterization of recycled coarse aggregate (RCA) via a surface coating method. International Journal of Concrete Structures and Materials, 8, 165–172.10.1007/s40069-014-0067-2 ↗
25. Shi, C., Li, Y., Zhang, J., Li, W., Chong, L., & Xie, Z. (2015). Performance enhancement of recycled concrete aggregate-A review. Journal of Cleaner Production, 12, 466–472.
26. Spanish Minister of Public Works. (2008). Instrucción de Hormigón Estructural EHE-08 (Spanish Structural Concrete Code).
27. Tam, V. W. Y., Tam, C. M., & Le, K. N. (2007). Removal of cement mortar remains from recycled aggregate using pre-soaking approaches. Resources, Conservation and Recycling, 50, 82–101.10.1016/j.resconrec.2006.05.012 ↗
28. Yang, I. S., Yun, H. D., Kim, D. S., Khil, B. S., & Han, S. G. (2005). Experimental study on engineering properties of concrete using fluosilicates based composite. Korea Concrete Institute Structure Journal, 17, 769–774.10.4334/JKCI.2005.17.5.769 ↗
29. Zhan, B., Poon, C. S., Liu, Q., Kou, S., & Shi, C. (2014). Experimental study on CO2 curing for enhancement of recycled aggregate properties. Construction and Building Materials, 67, 3–7.10.1016/j.conbuildmat.2013.09.008 ↗
30. Zhang, J., Shi, C., Li, Y., Pan, X., Poon, C. S., & Xie, Z. (2015). Performance enhancement of recycled concrete aggregates through carbonation. Journal of Materials in Civil Engineering. https://doi.org/10.1061/(ASCE)MT.1943-5533.0001296 .10.1061/(ASCE)MT.1943-5533.0001296 ↗