Evaluation of the mechanical behaviour of cement - stabilised collapsible soils treated with natural fibres

Studying the effect of different percentages of mixing rice straw fibres (RSF) on the compressive strength (CS) of collapsible soils stabilised with different amounts of cement through performing unconfined compressive strength (UCS) test and standard compaction test (SCT) form the basis of laboratory research in this project. The purpose of the use of natural fibres in this study is to achieve sustainability objectives in geotechnical engineering. The variable parameters of the study include the fibre content (0%, 0.25%, 0.5% and 1%), the cement content (0%, 4%, 8% and 12%), and the curing time (0, 7, and 28 days). In the sample containing only 1% of fibres, increasing the amount of cement from 0% to 12% improved the compressive strength by 172.38% and decreased the failure strain (FS) by 68.10%. The response surface methodology (RSM) was also conducted in the present study to identify the influence rules of cement content, curing time, fibre content, and their interactions on CS and FS. RSM is considered a confident method, since in both models, the P-Values are less than 0.0001, and the R-2 index for CS and FS equals 0.9893 and 0.9776, respectively.