Experimental analysis of the addition of rice husk ash to the clayey subgrade of a road stabilized with lime

S Vizcarra,I Lujan,M Soto,G Durán

doi:10.1088/1757-899x/758/1/012090

S Vizcarra, I Lujan + Show 2 more

Open Access

https://doi.org/10.1088/1757-899x/758/1/012090

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Abstract

There are many studies about how the addition of lime and rice husk ash (RHA) gives the soil a better mechanical behavior, particularly on clayey soils, where usually fine particles reach more than 75%. However, the soils with a small presence of fine particles (59-60%) do not have much research. This analysis evaluates the influence that RHA has on this kind of soil stabilized with 3% of lime. After the initial mix of soil-lime, CBR increased 11.2 times its initial value; within the addition of the ash, the CBR averaged between 45-50% up until 28% of RHA was added, where the results decreased considerably. Soil workability improved and the specimens with more ash resulted in a more granular material, with a group index value 0 following the AASHTO standards. The greatest CBR record was obtained with the specimen of 16% RHA, 3% lime and soil, reaching a 51.3% CBR, 1.58g/cm3 of MDD and 16.5% of OMC. Yet, it only showed a 1.55% more resistance than the lime-soil specimen. The CBR with more presence of RHA tends to decrease its value, therefore for silica-rich clayey soils, the addition of lime by itself should be enough for an adequate performance.

Highlights

There are currently a variety of problems facing civil engineering in terms of road infrastructure: cuts, landfills, earthworks, land stabilization, etc
There are many studies about how the addition of lime and rice husk ash (RHA) gives the soil a better mechanical behavior, on clayey soils, where usually fine particles reach more than 75%
Regarding the mixture R28C3 with the rest of the combinations used, the Maximum Dry Density (MDD) continues to decrease in a controlled manner, the Optimum Moisture Content (OMC) increases drastically to 25.10%, generating a decrease in the CBR to 32.90%

Summary

Introduction

There are currently a variety of problems facing civil engineering in terms of road infrastructure: cuts, landfills, earthworks, land stabilization, etc. The production of 80 tons of rice, generates 20 tons of rice husk, which can be reduced by up to 15% after incineration producing RHA [3] It is well known, that the RHA is rich in silica, bordering 90% of its composition, which is a higher concentration of SiO2 than fly ash [4, 9, 10]. That the RHA is rich in silica, bordering 90% of its composition, which is a higher concentration of SiO2 than fly ash [4, 9, 10] This characteristic of the ash shows its benefits when mixed up with CaO, for the pozzolanic reaction that occurs when both silica and calcium are combined. This article shows the effects of RHA on lime stabilization of a clayey road with 49.1% of sand

Experimental investigation

Other metals

Results and discussion

Conclusions