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From Sewage Sludge to Concrete09-09-15 | News

From Sewage Sludge to Concrete
May Be a Useful Ingredient

Researchers in Malaysia produced domestic waste sludge powder, ground and sieved it, and then mixed it with cement to produce different types of concrete.

The search for better alternatives for the disposal of sewer water sludge from wastewater plants may provide the hardscape industry with a replacement for cement in the manufacturing of concrete.

In a study published in the Pertanika Journal of Science and Technology, researchers from Universiti Teknologi MARA in Selangor, Malaysia investigated the potential of sludge as an alternative cement material for making concrete. According to the institution's Kartini Kamaruddin, the construction sector is seeking economic and ecological cement replacement materials in order to meet an increasing demand for concrete.

To find out if sewer water sludge fits that bill, the researchers first produced domestic waste sludge powder (DWSP) by drying and burning wet sludge cake to remove moisture, and then grinding and sieving it.

Using different proportions of the powder, the team mixed it with cement to produce different types of concrete (normal strength Grade 30 and higher strength Grades 40 and 50). They then compared each concrete mixture with normal concrete in terms of their compressive strength, water absorption, water permeability and permeability to salt.

The team found that the compressive strengths of DWSP concrete decreased as the proportion of DWSP increased in concrete mix, with the exception of Grade 40 concrete containing 7% DWSP. Also, both water absorption and water permeability increased as the percentage of DWSP increased. However, normal concrete was more permeable than DWSP concrete of Grade 40, suggesting that DWSP enhanced the durability of this concrete. Additionally, the resistance to salt permeability increased for concretes with up to 15 percent DWSP.

"Overall, there is potential for using DWSP as a partial cement replacement. However, more detailed research should be conducted to yield methods for producing quality powder," the researchers concluded.

Pertanika Journal of Science & Technology is published by Universiti Putra Malaysia in English twice a year in January and July. The stated goal of the journal is to provide a forum for high quality science and engineering research.