Flexural Strength of Sewage Sludge Ash (SSA) Concrete

Abstract

Studies about the sewage sludge becoming popular since the sewage sludge can be treated to produce sewage sludge ash (SSA) which has the potential to replace a percentage of cement.This study focuses on the flexural strength of the sewage sludge ash (SSA) concrete for 3, 7 and 21 days of curing relatively to its density.In this study 10 percentages of SSA was used as a replacement to cement and fine aggregates.SSA had known to exhibits pozzolanic properties similar to Ordinary Portland Cement (OPC). SSA was also used to replace the fine aggregates sinceby products of incineration as the particle size distribution has similar sizes to fine aggregates normally used in concrete mix. Besides, many studies also mention that SSA used in concrete may produce lightweight concrete. The SSA was incinerated at 1000°C for 2 hours followed by cooling in open air. Some of the SSA was sieved to be used as fine aggregates and some was grounded to be used as cement. Number of sample that was prepared for this study was 14 and it was design to achieve compression strength of 30MPa at 28 days based on DOE method. The flexural strength of concrete for cement replaced with SSA was lower than the control sample but it has an early flexural strength. The flexural strength of concrete for fine aggregate replaced with SSA was higher compared to the control sample.