Effect of white cement bypass dust on the degradation of roller compacted concrete subjected to sulphate attack

ABSTRACT

Large amounts of waste white cement bypass dust (WCBPD) are generated in huge heaps near white cement factories in Jordan, posing growing environmental concerns related to potential hazardous impact and additional disposal cost. This research evaluates possible and suitable recycling of WCBPD as a partial replacement of Portland cement in the production of the rapidly expanding roller compacted concrete (RCC). This experimental work aims to test the influence of using different proportions (10, 20, 30, and 40%) of WCBPD on the mechanical performance and durability of RCC subjected to sulphate attack. The investigation included compressive strength, a non-destructive test (ultrasonic pulse velocity), water absorption coefficient, and the sulphate linear expansion test. The experimental results were promising for recycling WCBPD as fractions of Portland cement in RCC mixtures at small amounts. Compared to reference cylinders, the reduction in compression strength was about 10, 28, 32 and 39% for 10, 20, 30 and 40% WCBPD replacement ratios, respectively. All RCC mixtures showed satisfactory sulphate resistance since no significant loss in compressive strength nor a significant increase in expansion ratio occurred due to sulphate exposure. The reductions in compressive strength at 180 days of sulphate exposure were 12.8, 15.6, 15.9, 16.1 and 16.6% for RCC cylinders prepared with WCBPD partial replacements of 0, 10, 20, 30 and 40%, respectively.

KEYWORDS:

• Roller compacted concrete
• white cement bypass dust
• sulphate resistance of concrete
• compressive strength
• recycling

Acknowledgements

The authors would like to acknowledge the Deanship of Scientific Research at Al-Zaytoonah University of Jordan for their financial support (Award No. 20/18/2018-2019) and the technical support provided by the laboratories of the Department of Civil and Infrastructure Engineering within the university.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by The Deanship of Scientific Research at Al- Zaytoonah University of Jordan [grant number 20/18/2018-2019].