Abstract:
Bottom ash (BA) and calcium carbide residue (CCR) are waste by-product form
the Mae Moh power plant in Lamphang, and acetylene gas factory in Nakhon Pathom,
respectively. This study investigated the possibility of using binder (B) to replace
cement in order to improve the compressive strength of soft Bangkok clay. The variable
used in this study is B composed of ground and unground BA and CCR, the SC: B ratios
of 50:50, 60:40, 70:30, 80:20, Used the ratio of OPC:BA and CCR : BA 70:30, 80:20, 90:10
and 100:0, water content of 1LL, 1.5LL and 2LL (LL is liquid limit of soft clay), water to
binder (W/B) ratio of 1 and curing time of 7, 28, 60 and 90 days. Scanning Electron
Microscope (SEM) and carbon footprint of sample were evaluated. The test results
show that the 7-day and 28-day compressive strength of sample increased as the B
content increased. SEM images show that C-S-H and ettringite products increased with
B content. The mix ingredient that offered the 28-day compressive strength more than
the DOH standard (1,500 kPa) was SC:B ratio of 70:30 and OPC:BA of 90:10 for all water
content which gave CO2 content of 410 kg/m3
. Finally, mix design charts for cement
column mixed with bottom ash and calcium carbide residue are proposed to meet
the target 28-day compressive strength and carbon dioxide emissions.