Use of Biopolymers in the Stabilization of Clay Soils

The treatment and stabilization of soils make it possible to recycle materials on construction sites in preparation for the installation of a final covering or the construction of a road network. In road geotechnics, various materials such as lime, cement, and pozzolans were used as additions to stabilize clay soils. In recent years, bio-polymers and bacteria are of increasing interest to researchers in the field of stabilization and improvement of the physico-mechanical and chemical characteristics of clay soils. Currently, in place of traditional clay treatment techniques and to minimize environmental problems, natural fibrous waste is being used increasingly and spectacularly. Several studies on biotechnological engineering applications already exist, such as the use of vegetation, algae, bacteria, enzymes, and biopolymers. The northern Algerian region where the urban tissue does not stop expanding contains significant potential in terms of wheat straw, which represents a very present agricultural waste. So, there is a local interest in the sustainable development of several regions known to produce wheat. This study is interested in investigating the effect of wheat straw on the stabilization of swelling clay soil. In order to improve the physico-mechanical characteristics of clay soils, a series of laboratory tests (Atterberg limit, Proctor test, direct shear test, Oedometer test, and unconfident compressive strength test) were carried out on reconstituted clay soil with defined initial properties through numerous analyses (e.g., XRD and XRF) and then treated with different vegetable fiber content. The results indicate that there is an improvement in the compressibility characteristics of the treated soil, a remarkable decrease in the swelling index and the compressibility index respectively with increasing percentages of wheat straw.

Utilization of Reclaimed Asphalt Pavement Material in Wet Mix Macadam (W.M.M)

Reclaimed asphalt pavement (RAP) is one of the innovative and effective technologies in many places in the world. The utilization of RAP is rapidly increasing popularity and becoming an emerging technique in India. As per IRC-120:2015, removing or reprocessing pavement materials containing aggregates that are bitumen coated is termed as RAP. These materials are gained through a process in which the existing surface pavement is reclaimed and reused after processing for reconstruction, resurfacing, or repaving. Well graded and high-quality aggregate are achieved from this process. Proper utilization of RAP with specified properties and specified percentages, not only serve as an alternative useful pavement material but also helps in reducing the usage of natural construction material, that will directly reduce the overall cost of projects. By conducting tests as per MoRTH specifications (5th Revision), the various characteristics of RAP material and fresh aggregates are observed. The main objective of the study is to carry out the performance tests: Modified Proctor test on fresh material as well as on material mixed with reclaimed asphalt pavement i.e. 10%, 20%, and 30% of total mix and to achieve optimum moisture content and maximum dry density by using Modified Proctor Test. Attempts are carried out to design a new pavement using Indian Road Congress (I.R.C-37:2018) guidelines and utilization of RAP material. Economic benefits are calculated in terms of fresh and RAP (10%, 20%, and 30%) mix material pavement.

Compressive strength of cement stabilizations containing recycled and waste materials

This study analyses the possibilities of using up to 30% of reclaimed asphalt pavement as a substitute material for natural aggregate, along with fly ash replacing 20% or 40% of Portland cement in cement stabilizations with 4% and 6% of binder. The Proctor test was used to determine maximum dry density and optimal moisture content of cement-based stabilizations. The compressive strength was tested after 7, 28, and 90 days. Parameters influencing 28-day compressive strength were evaluated by full factorial design and by classification in strength classes. The results obtained justify the utilisation of waste and recycled materials in pavement structures.

Improvement of Soil by Using Natural Material (JUTE AND GYPSUM)

Generally clay exhibits undesirable engineering properties like poor bearing capacity and higher compressibility. Thus the improvement of the soil at site is indispensable. There are many stabilizers to improve the strength of soil like Jute, Gypsum, fly ash, rice husk ash, cement, lime used rubber tyres etc. In the present Study , we added jute and gypsum as stabilizer to improve the properties of clayey soil . Locally available clayey soil is used in this study . The objective of this study is to improve the strength of the clayey soil by making soil-jute and soil-jute-gypsum mixture. six specimens are prepared to investigate the properties of soil out of which three specimens are prepared by adding 1% of jute with varying length of 1cm,2cm and 3cm and the remaining three specimens are prepared by adding 1% jute and gypsum each with varying length of 1cm,2cm and 3cm of jute . Standard proctor test and unconfined compressive strength test are conducted to analyse the optimum moisture content (OMC), Maximum dry density (MDD) and compressive strength of soil mixture.

Comparative study on Design of flexible pavement by various methods (GI method & CBR method)

In the project report, an attempt is made to design a road, based on the principles of pavement design and cost analysis of y two methods (Group Indexed and CBR Method). On the existing alignment of the road, soil samples are collected for the determination of soil characteristics like consistency limits, sieve analysis, C.B.R. values etc. Based on this the thickness of the pavement (flexible) is designed. The alignment of the road is also designed and fixed by surveying and leveling. The total road length being 497 meters of which, one section is 247m, other is 200m and the third section is 50m. The site selected for this study is of village road near Korba, Korba district of Chhattisgarh, India. Keywords: GI Method, Flexible Pavement, CBR Method, Liquid Limit Test, Plastic Limit, Standard Proctor test, OMS & MDD.

Experimental Investigation on Unconfined Compressive Strength of Cemented Soils Admixed with Saturated GAC

This research investigated the compressive strength of cemented soils admixed with saturated granular activated carbon (GAC). The saturated GAC was obtained from the water filtration system. A series of unconfined compressive strength was performed on both compacted soil-cement specimens and compacted soil-GAC-cement specimens with GAC content of 30 percent. All specimens were prepared by compaction with energy equivalent to the modified Proctor test. The results from modified Proctor tests showed that the maximum dry unit weight and the optimum moisture content of soil-GAC sample was less than those of soil sample. From the unconfined compression tests, there was tiny development of strength for both types of specimens with cement content of 1 percent throughout the curing period of 28 days. For both types of specimens with cement content of 2 and 3 percent, the significant development of strength occurred after curing for 3 days. The strength of specimens typically increased with increasing cement content. Generally, the strength of compacted soil-GAC-cement specimens was less than that of compacted soil- cement specimens. It was also observed that the relationships between normalized compressive strength ratio and curing period was unique for the specimens with the same cement content.

Wood Fly Ash Stabilized Road Base Layers with High Recycled Asphalt Pavement Content

Wood fly ash stabilised road base layers with high recycled asphalt pavements content was studied both at the laboratory and in-situ. The original recipe was chosen based on an actual stabilised pavement base layer design with cement CEM II/B-T 42.5R but optimised using wood fly ash. The existing road base layer from gravel was mixed with dolomite aggregate and recycled asphalt pavement, adding cement and wood fly ash at different proportions. The mixture was compacted at optimal water content according to the Standard Proctor test and further conditioned. Resistance to freezing and thawing of hydraulically bound mixtures was checked after 28 days of conditioning. Even 50 cycles of freezing and thawing were used. Test results indicated wood fly ash as an effective alternative to the typically used cement for road base stabilisation, including recycled asphalt pavement material. Three hydraulically bound mixtures were chosen for test sections in the pilot project. The project includes five different sections with three different hydraulic binder recipes. The performance of each section was evaluated.

A Experimental Study of Laboratory Compaction and Sand Cone on Foundation Tub Soil

Soil is a very important material so that it must be able to support the loads above it, so the soil must have a sufficiently good soil bearing capacity. In this study, the soil compaction was compared with the laboratory compaction method with the sandcone method. The objectives of the study were knowing the characteristics of the soil and knowing the laboratory compaction compares with the sandcone compaction in the foundation tub. Soil is drawn from the same point for the Proctor Test and Sand cone Test. The results of this test are used in the foundation model test. Characteristics testing in the laboratory: moisture content, density, consistency limits (LL, PL), sieve analysis, hydrometer, laboratory compaction and sandcone. Research result It was found that the soil type was based on the AASHTO classification was A-7-5 and the soil classification based on the Unifield Soil Classification System (USCS) was MH. Laboratory compaction (Proctor Test) average moisture content of 32.26%, γd maximum 1.33 g/cm³, and the sandcone compaction of model foundation test of soil without foundation ɣd was 1.36 g/cm³ , Vertically arranged tire foundation ɣd was 1.36 g /cm³ , horizontally arranged tire foundation ɣd was 1.36 g /cm³