Permeability Analysis of Dredged Material and Its Stabilization Using Surkhi/Brick Dust

This study presents the permeability and strong relationship of dredged soil stabilized with surkhi/brick dust which is to be used for constructing road embankments. Tests like the unconfined compressive strength test and the falling head permeability test were conducted. The test results showed that as the percentage replacement of surkhi increases, the samples become less permeable. Showing that the surkhi tends to cover up the pore spaces of the soil, causing the water to have fewer passageways. Large amount of sediments are dredged from rivers and lakes as a result of environmental dredging in India. These dredged materials (DM) have poor Geotechnical properties and are normally treated as wastes. On the other Hand, there is a huge demand of sub-grade materials due to the increasing number of highway construction projects in the J&K. Thus, the reuse of the dredged material as sub-grade material may be considered as an Environmental-friendly and economical option. For the stabilization of dredged material various waste materials can be effectively used. brick dust is one such waste product. The surkhi/brick dust is generated from brick kilns. The amount of brick dust produced every year is in the range of 3-4 million ton. This project therefore intends to study the stabilization of dredged material procured from Sindh Nallah having a higher content of alluvial Soil using Surkhi/Brick dust as an additive. Soil stabilization by this means can be utilized on airport pavements, highway pavements, earthen dams and many other situations where sub-soils are not suitable for construction. Keywords: dredged material Sindh Nallah, surkhi, Dredged soil, CBR, UCS, proctor test, porosity, void ratio and permeability

Sustainable Reuse of Dredged Soil as a Substrate Material by Improvement with Polyacrylamide, Straw, and Superabsorbent Polymer

Every year, a significant quantity of dredged soil is generated as a result of channel dredging operations. However, there is relatively little evidence available regarding the sustainable reuse of dredged soils. In this study, an improved substrate material mainly composed of dredged soil was developed to examine the effects of three substrate amendments on the soil’s nutritional content, physical properties, and water retention capacity, as well as the germination rate of tall fescue. The orthogonal combination of the three substrates was controlled in a pot experiment using polyacrylamide (PAM), rice straw, and superabsorbent polymer (SAP) at application rates of 0.5, 1, 1.5, 2, and 2.5 g/kg; 15, 20, 25, 30, and 35 g/kg; and 0, 3, 6, 9, and 12 g/kg, respectively. The results showed that adequate application of PAM may improve the water retention capacity and available N retention capacity of dredged soil. PAM inhibited tall fescue germination significantly when the concentration exceeded 0.5 g/kg ( p < 0.05). The addition of rice straw significantly improved the nutritional content of dredging soil and the germination rate of tall fescue ( p < 0.05). Increased SAP significantly decreased the bulk density of dredged soil ( p < 0.05). The lowest test group was 48.20% less than CK. This study offers novel ideas for the sustainable reuse of dredged soil and serves as a guide for future research aimed at increasing the effectiveness of external-soil spray seeding technologies.

Properties of locally available river dredged soil stabilized with cement

In Bangladesh, the topsoil of agricultural land is being used to manufacture burnt clay bricks for a long time. This is one of the major reasons for reducing the cultivable land every year. But, we have a huge amount of River Dredged Soil (RDS) available that could be used for manufacturing building materials as an alternate to the conventional bricks. In this regard, the present study has been performed to investigate various properties of RDS from the Brahmaputra River and different mixes of RDS containing different percentages of cement content. The physical properties such as specific gravity, unit weight, mean diameter, maximum dry density and optimum moisture content of RDS were determined following standard procedures. Cylindrical specimens of RDS were prepared by mixing with different amounts of cement content. All the specimens were cured for 7, 14, and 28 days before testing. Water absorption of the RDS-cement specimens after 28 days was found between 14 to 18% which is in the range of first-class burnt clay brick. It was found that the water absorption decreases with the increase in the percentages of cement content. The unconfined compressive strength was observed to increase with the increment of cement content as well as curing age. The maximum unconfined strength was recorded for the specimens containing 14% cement and the rate of strength increment was about 45% in two weeks. It means the addition of cement with RDS will definitely increase the strength. But, the maximum use of cement must be decided based on the required strength and economic consideration. The deformation at failure was found decrease with the increase in cement content. This indicates that the stiffness of the stabilized RDS would increase upon the increment of cement content. Based on the above test results, it is concluded that the dredged soil from Brahmaputra River can be stabilized with cement for making compressed earth block which would be an alternative to the burnt clay brick that uses valued agricultural soil as raw material. Progressive Agriculture 32 (1): 71-77, 2021