Highway Research Record

VI. RESEARCH WORK DONE IN ACADEMIC INSTITUTIONS RELATED TO THESIS WORK
B. PAVEMENT ENGINEERING AND PAVING MATERIALS
GIS Based Study on the Engineering and Chemical Properties of Seashore Soil and its Improvements

Date of Start:July 2004
National Institute of technology, Tiruchirappalli (R,S)

Scope and Objective
(i) Identification of Engineering and chemical properties of sea shore soil.
(ii) Identification of suitable stabilizer and stabilization of sea shore soil with suitable stabilizer.
(iii) Strength tests after stabilization.
(iv) Preparing Soil Map using GIS.

Methodology
Identification of engineering properties of sea shore soil through laboratory tests and identification of suitable stabilizer. After stabilization the strength is checked by lab tests.
For phase I of the project, six samples were collected from Pudhukkottai and Tanjavur districts. Laboratory tests were conducted to identify the engineering properties of the soil sample. Based on the engineering properties, the suitable stabilizer was selected.
For phase II of the project, 23 samples were selected from Nagappattinam District. Laboratory tests were conducted to identify the engineering and chemical properties of the soil samples. Based on the engineering and chemical properties, the suitable stabilizer was selected. The strength tests were conducted after stabilization.

Findings and Conclusions

Tanjavur and Pudhukkotai seashore soil is a weak soil. The suitable stabilizer identified is cement. The samples from the Thanjavur and Puthukkottai district are unsuitable for sub grade, sub base and base courses without stabilizing with the cement. An increase in cement percentage increases the optimum moisture content and slightly decreases the maximum dry density.

CBR value is improved significantly on addition of 2-6% cement under worst moisture condition of 4 days soaking. The CBR value of the 6% cement treated soil is more than 125% in all the three samples. The field CBR is only 50% of Laboratory CBR. Hence it is advised to design the pavement only on 50% laboratory CBR value.

Nagappattinam district samples are also weak soil. The CBR values varies from 1.7% to 5.4%.The plasticity index value varies from 4 to 19 for various samples. UCC values varies from 1.37 to 3.73 kg/cm2.The maximum swell pressure is 0.31 kg/cm2.The total soluble solids in all the samples are 3 to 4%.Organic matter present in the samples are 2 to 4%.

Suitable stabilizer identified for the Nagappattinam samples are cement,fly-ash,calcium chloride and sodium chloride. With addition of 8% cement the UCC value increases upto 7.5 kg/cm2. With addition of 3% fly-ash the UCC value increases up to 7.26 kg/ cm2 from 1.47 kg/cm2. 4% cement and fly-ash addition increases the CBR value up to 60% from 2.5%.