Environmentally friendly unburnt bricks using raw rice husk and bottom ash as fine aggregates: Physical and mechanical properties

  • Ngo Si Huy Department of Engineering and Technology, Hong Duc University, 565 Quang Trung street, Dong Ve ward, Thanh Hoa city, Vietnam
  • Nguyen Ngoc Tan Faculty of Building and Industrial Construction, National University of Civil Engineering, 55 Giai Phong road, Hai Ba Trung district, Hanoi, Vietnam
  • Mai Thi Ngoc Hang Department of Engineering and Technology, Hong Duc University, 565 Quang Trung street, Dong Ve ward, Thanh Hoa city, Vietnam
  • Le Ngoc Quang Urban Management Office of Thanh Hoa City, Nguyen Hoang Avenue, Dong Hai ward, Thanh Hoa city, Vietnam

Abstract

In order to reduce the serious impacts of industrial and agricultural wastes on the environment, raw rice husk and bottom ash were used as fine aggregates, while fly ash was utilized as a binder material in the production of unburnt building bricks. Two group mixtures were designed with water-to-binder (W/B) ratios of 0.30 and 0.35. The rice husk was used to replace 0%, 3%, 6%, and 9% of bottom ash content by mass. An experimental program was carried out on the brick samples at different ages from 3-day to 28-day to determine the main physical and mechanical properties of brick, such as unit weight, compressive strength, water absorption, ultrasonic pulse velocity and thermal conductivity. The microstructure of brick material was captured using scanning electron microscope technique. The experimental results allow to identify the effects of rice husk, bottom ash content as well as W/B ratio on the properties of bricks. Brick samples produced in this study had a proper compressive strength meeting the practice requirement and were classified as Grade M3.5 and 5.0 based on TCVN 6477:2016. At the use of 9% rice husk, the unit weight and thermal conductivity of bricks were really low (1.06÷1.08 T/m3 and 0.201÷0.216 W/m.K), they are conformed to be used in temporary construction and insulation structures.

Keywords:

rice husk; bottom ash; fly ash; unburnt brick; ultrasonic pulse velocity; thermal conductivity.

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Published
22-01-2021
How to Cite
Huy, N. S., Tan, N. N., Hang, M. T. N., & Quang, L. N. (2021). Environmentally friendly unburnt bricks using raw rice husk and bottom ash as fine aggregates: Physical and mechanical properties. Journal of Science and Technology in Civil Engineering (STCE) - NUCE, 15(1), 110-120. https://doi.org/10.31814/stce.nuce2021-15(1)-10
Section
Research Papers