Sudipta Sarker - Research

Research

Water quality implications of land conversion to corn-soy cultivation in northeast Kansas

Due to the high demand of biofuel, corn belt is dynamically expanding towards its periphery in the midwestern USA. As the center of the corn belt has become saturated with corn and other bio feedstock production, a peripheral shift makes Kansas a potential area for biofuel production. In fact, northeastern Kansas has experienced an increase in agricultural production in recent decades. However, the water quality impacts of biofuel-based landuse scenarios (increased rotational corn-soybeans production) at watershed scale is largely understudied. This study focuses 2924 km2 Delaware River Watershed located in northeastern Kansas which drains into Perry Lake, a regionally important reservoir further drains into the Kansas River. Our 15-years (2006-2021) land use change analysis revealed a significant grassland to corn-soy conversion rate (15% reduction and 12% increase respectively) which is causing return of CRP land into farming. Based on land use change intensity and accessibility of the location, 30 sampling sites were selected for seasonal synoptic sampling from Fall 2020 to Summer 2022 to capture the effect of land use change on water quality. Based on the experimental results of water quality parameters (total phosphorous, soluble reactive phosphorous, nitrate and other environmentally relevant anions, total and dissolved organic carbon, total suspended solid, organic matter percentage etc.) and the location of the sites, the whole watershed was delineated into 30 subwatershed and water quality parameters were used to correlate with the land use change occurred in the subwatershed scale. In the next phase of our study, a water quality model will be developed to determine the extent of biofuel expansion based on the water quality data and land use analysis. It can reveal sustainable extent of renewable fuel growth towards the periphery of corn belt and whether Kansas can be the next hub of biofuel expansion.

Salinity Removal of sea sand and its (both washed and unwashed) feasibility to use in concrete

The rapid growth in the expansion of the construction work is leading to a depletion of natural resources like river sand. This overuse should be balanced by introducing certain abundantly available other natural materials which can replace the river sand
     Another problem is the emission of CO2 associated with the production of cement. One way to reduce the global cement use is to use other supplementary cementitious materials in the construction work. The coal-based power plant produces a huge amount of fly ash that creates its disposal problems but at the same time, it can be utilized as a partial substitution to cement.
    The alkali-activated fly ash concrete (Geopolymer Concrete) shows considerable promise for application in the construction industry as an alternative to OPC.        In this experimental work, the chloride content of sea sand from different region of Chittagong & Cox’s Bazar is determined and its removal techniques are discussed.
     The sea sand (washed and unwashed) has been used as an alternative to river sand and strength properties of OPC and geopolymer concrete are studied.
Presentation link:
drive.google.com/open?id=1u9lcC6YxL5InUB4MgpaKhIikLfi9MARQ

Development of non-fired brick by replacing conventional agricultural clay with potential waste materials

Demand for bricks is on rise, following the growth of the construction industry amid in infrastructure boom in Bangladesh. Bricks produced from traditional technique and agricultural clay contributes mightily to what is considered some of the worst air pollution in the world. Every year an estimated 25 billion pieces of conventional bricks are manufactured in this country. This process emits 15 million tonnes of carbon into the air and requires 100 million tonnes of topsoil.
Thus, this highly energy and resource intensive conventional clay brick production process has a great effect on agricultural production and environment and thereby achieving sustainable development. There is an urgent need to start using environment-friendly alternative instead of conventional bricks to save the fertile topsoil and conserve a clean environment. This research therefore is aimed to explore different options to produce non-fired bricks. The study incorporated different types of industrial waste including fly ash, Induction Furnace Slag (IFS), Ladle Furnace Slag (LFS) and Ground Granulated Blast Furnace Slag (GGBFS) as a full or partial replacement of cementitious media such as Portland based cement and lime powder in mortar and non-fired building block manufacturing process in laboratory scale. The incorporation of abundant steel and power plant solid waste in brick could be a potential solution for the management of these hazardous residues.
The prepared samples without using any agricultural clay conforms to the minimum compressive strength requirement of 10.3 MPa as per ASTM C62 and BDS 208 with a maximum compressive strength of 40.6 MPa for building block and 49.1 MPa for geopolymer mortar. This highly promising performance pronounced the use of industrial waste materials in non-fired brick production to achieve a cleaner, environmental friendly sustainable society as well as a potential waste management approach for hazardous industrial waste.
Final technical report link:
https://drive.google.com/file/d/1scRMzAEs42rlOGCxYxBIZFD4ennYiHIA/view?usp=shari

Effects of elevated temperatures on the Compressive strength of Basalt FRP Concrete Column bonded with Geopolymer Resin

The topic of this research explores the effects of elevated temperatures on the compressive strength of concrete cylinders retrofitted with Basalt Fibre-Reinforced Polymers (BFRP) bonded with a geopolymer paste. This was achieved by conducting laboratory-based work whereby standard concrete cylinders were casted and cured, which were then retrofitted with BFRP (single and double layered) bonded with both epoxy and geopolymer pastes. The specimens were then heated to elevated temperatures for a set period before being allowed to cool to room temperature and then tested under compression. The epoxy resin specimens were used as a means of comparing the current industry methods for retrofitting FRP.
The results indicated that beyond the glass transition temperature of the epoxy resin, both the single and double layered specimens had a significant dip in their increase in strength. On the other hand, the strength of the geopolymer specimens remained relatively constant due to its high thermal resistivity. Although the geopolymer specimens displayed weaker compressive properties at lower temperatures, the instability of the epoxy specimens had allowed the geopolymer specimens to possess a higher compressive strength at the elevated temperatures tested. The basalt FRP had shown significant strengthening properties that were comparable to that of glass FRP, but a cost analysis conducted showed that the BFRP was the most cost-effective reinforcing fabric of the three fabrics that were investigated.
The research was successful in that the independently studied geopolymer was combined with the research related to FRP reinforcement to yield positive results. This is very significant as in addition to the research conducted on BFRP which is relatively new to the market, the results from the experiments could be used in further research to test other mechanical properties. If the relationships and trends remain the same for the other properties tested, then it can be said that a cheaper, environmentally friendly alternative can be used in the FRP retrofitting that is capable of withstanding elevated temperatures in addition to its other resistive properties. This new research would aid the industry in seeking alternative methods for retrofitting concrete that needs additional reinforcement.

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