EXPERIMENTAL STUDIES ON
UTILIZATION OF MURRUM AS HARD
SHOULDER MATERIAL
PRADEEP MULEY
PG Student
Department of Civil Engineering M.A.N.I.T Bhopal, M.P. India 462051
Dr. P.K. JAIN
Associate Professor Department of Civil Engineering M.A.N.I.T Bhopal, M.P. India 462051
Mr. RAJEEV JAIN Reader
Department of Applied Mechanics and Structure S.A.T.I. Vidisha, M.P. 464001
ABSTRACT
Murrum is widely used material for the construction of pavement shoulders. Sometimes the available murrum may not satisfy the requirement of CBR and hence need to be modified. The locally available granular material like sand and/ or the crusher dust may be mixed to the soil to obtain the desired characteristics. The paper discusses results of the experimental study in which the quality of local murrum has been improved by adding stone dust. The index properties, compaction characteristics and California Bearing Ratio (CBR) parameters for the murrum blended with varying percentages of the stone dust has been presented and it is shown that the utility of the soil as a road material has been increased greatly by simple mixing of the granular material. Keywords: Murrum, Stone Dust, Hard shoulder, GSB and CBR.
1 INTRODUCTION
The materials available for the construction of road are fine gravel, clay and sand or stone dust. The variable mixtures of sand, dust silt and gravel could be successfully used for pavement construction, while the stone dust forms an excellent material for slope protection. This is suitable for the construction of pavements. Clays are quite impervious, but they lack in weight and stability and tend to swell and slump when saturated with water and to shrink and crack when dry (Sundar Kumar and Ratnakanth Babu, 2010). The Lateritic soil is popularly known as murrum. It is characterized by a deep weathered layer from which silica has been leached. There is no humus, but an accumulation of aluminium and iron oxides and hydroxides. The reddish colour of these soils is imparted by the iron compounds. Murrums are residual soils and are formed from weathering of basaltic rock at places, where monsoon is severe (Ketkar, 1970). They constitute mixture of weathered rock pieces in varying sizes, sand, silt and clays. They are good material for road construction.
2 EXPERIMENTAL INVESTIGATIONS
2.1 Material Used
The murrum soil and stone dust used in this study was collected from Vidisha-Bhopal National Highway (NH-86) near Salamatpur Railway station in Madhya Pradesh and the stone dust was collected from the crusher situated at Salamatpur Railway Station. The properties of murrum and stone dust are presented in the table 1 and 2 respectively.
Table 1 Properties of the Murrum
Property Result
Specific Gravity 2.66
Gravel 7.6% Sand 78.6%
Silt 10.3% Clay 3.5%
Liquid limit 41%
Plastic limit 19%
Plasticity index 22%
Classification Group SC
OMC 13.00%
MDD 1.62 g/cc
Soaked CBR 10.94%
Table 2 Property of the Stone Dust
Property Result
Specific Gravity 2.66
Gravel 00.0%
Fine Sand 26.2
Fines 73.8%
OMC 10.22 %
MDD 1.90 g/cc
Soaked CBR 58%
2.2 Details of the Test Variables
In the present work, murrum was physically stabilized by adding 10%, 20%, and 30% of stone dust by weight of the soil.
3 ANALYSES OF TEST RESULTS
3.1 Effect of Mixing Stone Dust on Index Properties of Murrum
Table 3. Values of Liquid Limit, Plastic Limit and Plasticity Index for murrum Mixed with varying percentages of stone dust
Test parameter
Stone Dust Mixed by weight of raw soil
0% 10% 20% 30%
Liquid limit, % 41 36 29 28
Plastic limit, % 19 19 18 17
Plasticity index , % 22 17 11 11
Fig. 1. Variation of Liquid Limit, Plastic Limit and Plasticity Index Values for Murrum Mixed with Varying Percentages of Stone Dust
It is observed that from the table 3 and fig. 1, that the liquid limit, plastic limit and plasticity index of murrum-stone dust mix decreases with increase in percentage of murrum-stone dust. The plasticity of the mixes is reduced due to increase in stone dust particles, a non-plastic material.
3.2 Effect of Mixing Stone Dust on of Compaction Characteristics of Murrum
IS heavy compaction tests were conducted on the murrum stone dust mixes considered in the investigation to determine the maximum dry density (MDD) values and optimum moisture content (OMC) values. The results are shown in table 4.
Table 4. Values of OMC and MDD for different murrum mixtures
Percentages of Stone Dust Mixed with
Compaction Properties
The variation of maximum dry density and optimum moisture content for varying percentages of additives are shown in figure 2 and 3. The MDD values are increasing and OMC values are decreasing with increasing percentages of stone dust added to the murrum. This is due to stone dust particles fills the voids of the coarse grained particles of the murrum.
Fig. 2. Variation of MDD values for Murrum Mixed With Varying Percentages of Additives
Fig. 3. Variation of OMC values for Murrum Mixed With Varying Percentages of stone dust
3.3 Effect of Mixing Stone Dust on CBR Properties of Murrum
Table 5.Values of CBR for different murrum mixtures
Percentages of Stone Dust Mixed with Murrum (%)
CBR, %
0 10.94 10 14.60 20 21.16 30 25.56
Fig. 4 Variation of CBR for Murrum Mixed With Varying Percentages of stone dust
In the construction of roads on poor soils such as highly plastic clays, borrowed earth layer known as the select soil needs to be laid. It should have soaked CBR more than 7. Further, the specifications for construction of roads mention that CBR for hard shoulder material should be more than 12. The murram used in the present study has CBR as 10.94 and as such, is usable as only select soil material. However, it may be seen from table 5 that by adding 10% stone dust, the material qualifies CBR requirement needed for hard shoulder.
As per MORD specifications, the granular sub base layer (GSB) used above sub grade should have CBR more than 20 for grade C and more than 25 for grade B quality. The results of murrum stone dust mixes show that this requirement is also met with by 20% and 30% stone dust respectively.
4 CONCLUSIONS
Based on the laboratory test results, the following conclusions are drawn:
1. As the percentages of stone dust increased in the murrum, the plasticity characteristics of the mixture decreases, MDD values increases and the corresponding OMC values decreases.
2. It is observed that the murrum of moderate CBR is improved significantly by varying quantity of stone dust. In the present study soaked CBR of murrum was 10.94 which has been increased to 21.16 to 25.56 on mixing 20% and 30% stone dust respectively by weight of raw soil.
REFERENCES
[1] IS: 2720 (Part-IV)-1985. “Indian Standard for Grain Size Analysis”, BIS New Delhi.
[2] IS: 2720 (Part-V)-1987. “Indian Standard for Determination of liquid limit and plastic limit”, BIS New Delhi.
[3] IS: 2720 (Part-VIII)-1983. “Indian Standard for Determination of Water Content-dry density relation using heavy Compaction”, BIS New Delhi.
[4] IS: 2720 (Part-XVI)-1974.”Indian Standard for Laboratory Determination of CBR”, BIS, New Delhi. [5] IRC 37-2001. “Guidelines for the Design of Flexible Pavements”, New Delhi.
[6] IRC:SP:20-2002. “Rural Roads Manual”, Indian Roads Congress, New Delhi.
[7] Ketkar, D. J. (1970), “Subsurface conditions-Bombay Island”, Symposium on Subsurface Exploration and Foundations of Structures in theBombay region, Indian National Society for Soil Mechanics and Foundation Engineering (Bombay Center), Vol.1, 1970.
[8] Sundar Kumar P and Ratnakanth Babu M.J (2010), “Experimental studies on utilization of murrum as embankment material”, International Journal of Engineering Science and Technology, Vol. 2 (7), 2010, 2600-2666.
