A Laboratory Study on the Performance of Mill Scale Dust on Improving the Properties of the Marine Clay as Subgrade for Flexible Pavements

Abstract

Globally, the Marine Clay is found in coastal areas. It is a problematic soil due to its varying moisture content and compressibility characteristics. In marine clays, the swelling and shrinkage behaviour is due to the clay mineral montmorillonite. Hence the constructions on the Marine Clay have become a challenging task for civil engineers. The Pavements on marine soils have low strength and highly compressible, resulting in poor performance and increased maintenance costs. Soil stabilization helps a lot in improving the strength characteristics of marine soil. Mill scale dust is a by-product from lathe machine workshops, which contains ferrous (Fe) predominantly, supports in improving the strength characteristics. In this investigation, the efficacy of mill scale dust has been studied for improving the strength parameters of the Marine Clay to suit it as subgrade for flexible pavements under cyclic pressures. In view of the recent developments in the coastal area, a great number of ports and industries are being created. The availability of land for the development of commercial, housing, industries and infrastructure etc., is limited. The scarcity of land become big task for civil engineers in civil engineering application and also become a challenged task for constructions of various structures in problematic soils. The Marine Clay is a kind of micro crystalline clay. It comprises clay minerals such as chlorite, illite, kaolinite, and montmorillonite, as well as non clay minerals such as quartz and feldspar. Because of the unpredictability associated with the performance of the Marine Clay, it provides significant challenges in pavement and foundation construction. Due to its poor technical qualities, employing the Marine Clay (locally accessible soils) as a sub grade in a coastal zone will not give appropriate results. Several corrective measures, such as soil replacement, will be implemented, in which weak soil particles will be removed and replaced with rich soil particles. However, this is not economically possible, because it raises the project\'s budget. So, to avoid this problem and to improve soft soils, there are several solutions available, one of which is soil stabilization using admixtures (industrial by-products) and certain chemical additions. In the present study an attempt has been taken to improve the properties of Marine Clay with the percentage variation of Mill Scale Dust. The Marine Clay exhibited suitable on addition of 25 % Mill Scale Dust as optimum. The treated Marine Clay as exhibited suitable CBR value as per codes of practice [IRC 37:2012] and this treated Marine Clay can be used as subgrade for flexible pavements. The cyclic plate load test were conducted on treated and untreated Marine Clay model flexible pavements in the laboratory. It is observed from the laboratory test results that the treated Marine Clay is more effective as subgrade for flexible pavements under cyclic pressures.

Introduction

The text focuses on the geotechnical challenges of Marine Clay and its stabilization using Mill Scale Dust (MSD) for road subgrade applications.

Marine Clay, found along India’s coastal regions, is a soft, highly compressible, moisture-sensitive soil with low strength and high swelling/shrinking behavior. These properties make it unsuitable for construction, especially for pavements and highways, as even small moisture changes can cause instability and structural damage. To improve its performance, soil stabilization using industrial waste materials is explored.

In this study, Marine Clay from Kakinada Port is treated with varying percentages of Mill Scale Dust, an iron-oxide by-product from steel rolling. Four mixes are tested: 0%, 15%, 20%, and 25% MSD.

A series of laboratory tests (as per Indian Standards) are conducted, including swelling tests (DFS), Atterberg limits, compaction tests (MDD and OMC), and CBR tests to evaluate strength and suitability for pavement subgrade use.

Key results show that adding Mill Scale Dust significantly improves soil properties:

• Differential Free Swell (DFS) decreases from 40% to 25%, indicating reduced swelling.
• Plasticity reduces, showing improved soil stability.
• Maximum Dry Density (MDD) increases from 1.601 to 1.986 g/cc, indicating better compaction.
• Optimum Moisture Content (OMC) decreases, meaning less water is needed for compaction.
• Overall, soil strength and engineering performance improve with higher MSD content.

The study concludes that Mill Scale Dust effectively stabilizes Marine Clay, making it more suitable for use as a pavement subgrade by reducing swelling and increasing strength while also utilizing an industrial waste material.

Conclusion

1) It is noticed from the laboratory test results the Differential Free Swell of Marine Clay has been improved by 37.5 % when compared with untreated Marine Clay. 2) It is noticed from the laboratory test results the liquid limit of Marine Clay has been decreased by 85.04 % when compared with untreated Marine Clay. 3) It is also observed from laboratory test results that the plasticity index of the treated Marine Clay has been enhanced by 75.03 % on addition of 25% Mill Scale Dust. 4) It is noticed from the laboratory test results the O.M.C of Marine Clay has been improved by 33.41 % when compared with untreated Marine Clay. 5) It is noticed from the laboratory test results the M.D.D of Marine Clay has been improved by 41.75 % when compared with untreated Marine Clay. 6) It is noticed from the laboratory test results the C.B.R of Marine Clay has been improved by 8.96 % when compared with untreated Marine Clay.

References

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Copyright

Copyright © 2026 Sajida Sulthana Mohammed, Harish Gangaraju, Dr. D. Koteswara Rao. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.