Papers by Prof. Dr. Md. Tarek Uddin , Professor, CEE
Doboku Gakkai Ronbunshu, 1998
Doboku Gakkai Ronbunshu, 1998
, Experimental Study on Interfacial Transition Zones in Reinforced Concrete.
Journal of Materials in Civil Engineering, 2014
ABSTRACT An extensive investigation was carried out for recycling of demolished brick aggregate c... more ABSTRACT An extensive investigation was carried out for recycling of demolished brick aggregate concrete as coarse aggregate. For this, demolished concrete blocks were collected from 33 different building sites of different ages and broken into pieces as coarse aggregate. Due to the lack of availability of stone aggregate in Bangladesh, most of the old structures are constructed with brick chips as coarse aggregate, therefore the recycled aggregate investigated in this study is different from the recycled aggregate investigated in other countries which are mostly made of stone chips. The properties of recycled aggregate, such as specific gravity, absorption capacity, and abrasion were tested. More than 700 cylinder concrete specimens of diameter 150 mm and height 300 mm were made with water-to-cement ratio 0.45 and 0.55. Concrete specimens were tested at 7, 14, and 28 days for compressive strength, tensile strength, and Young's modulus. The results are compared with virgin brick aggregate. Extended study was also conducted on partial replacement (10% 50%) of virgin brick aggregate with recycled brick aggregate. Also, in-situ strength of an old structure has been compared with the compressive strength of recycled aggregate concrete made with the recycled aggregate collected from the same structure. Based on this investigation, it is revealed that recycled brick aggregate can be used as coarse aggregate for making concrete of strength 20.7 to 31.0 MPa. For the same mix design, the recycled aggregate concrete produces almost similar strength compared to the virgin first class brick aggregate concrete commonly used in Bangladesh. However, relatively better performance of recycled aggregate concrete is found for W/C = 0.45. No significant change in compressive strength of concrete is found for up to 50% replacement of virgin aggregate by recycled aggregate. By recycling, it is possible to make concrete with more strength compared to the in-situ strength of concrete of old structures.
Capital city of Bangladesh, Dhaka has experienced a rapid growth of urban population. Due to the ... more Capital city of Bangladesh, Dhaka has experienced a rapid growth of urban population. Due to the scarcity of land in the city, it is indispensable to construct high rise buildings to accommodate the population in the city. For construction of high rise buildings, high strength concrete mix proportions are to be developed using the locally available construction materials. With this objective, this study has been planned. Cylinder concrete specimens of diameter 100 mm and height 200 mm were made with different mix proportions of concrete. The variables that have been studied were W/C (from 0.55 to 0.35), cement content (from 350 kg/m3 to 500 kg/m3), sand-to-aggregate volume ratio (from 0.34 to 0.38), type of cement (ordinary portland cement, blended cement with different proportions of fly ash, ground granulated blast furnace slag, and silica fume), different types of aggregates (stone chips and brick chips of different quality). Before making concrete specimens, a grading that gives maximum unit weight of the aggregate, i.e., minimum void in aggregate was developed both for fine and coarse aggregates. All aggregates were also investigated for unit weight, absorption capacity, and abrasion value. Fresh concrete was tested for workability using a slump cone. Concrete cylinder specimens were tested for compressive strength, tensile strength, and stress-strain characteristics at 28 days. The results revealed that it is possible to get strength of concrete up to 7000 psi using the locally available materials used in this study. To achieve further strength, it is necessary to use good quality coarse aggregate with lower value of abrasion.
The quality of cement is one of the important factors related to the strength and durability of c... more The quality of cement is one of the important factors related to the strength and durability of concrete. In Bangladesh, there are more than 60 cement companies those are producing cements with different composition and supplying to the market with different brand names. However, no comparative study has been made to check the quality of the cement brands available in the market. As a part of a research project on sustainable development of concrete construction works in Bangladesh, this study has been planned. For investigation, cement bags were collected from thirty different companies with different brand names. The composition of the cement has been recorded from the cement bags. Each of the cement samples (collected as bags from market) has been tested in the laboratory for bulk unit weight, normal consistency, initial setting time, final setting time, bleeding, fineness, and compressive strength at 3 days, 7 days, 14 days, and 28 days as per ASTM standards.Test results indicate that a cement brand with a longer final setting time and more bleeding gives less compressive strength at 28 days. A linear correlation is found between the 28-day compressive strength and final setting time of cement. By using this correlation, it will be possible to determine the compressive strength of cement at 28 days by quick determination of final setting time in the laboratory. Correlations between strength of cement with time are developed for different cements that can be also be used for predicting 28-day strength from the result of early strength of cement, such as 3-day or 7-day.
Due to the construction of buildings and other infrastructures in the major cities in Bangladesh,... more Due to the construction of buildings and other infrastructures in the major cities in Bangladesh, it is found that the uncovered ground area for infiltration of rain water to ground water reservoir is reduced significantly. On the other hand, continuous sucking of ground water from underground reservoir results in depletion of ground water level year by year. This environmental problem can be reduced by application of porous concrete on parking areas, walkways, and roads for light vehicles, etc. With this background, this study on pervious concrete has been planned. Cylinder concrete specimens of diameter 100 mm and height 200 mm were made with locally available coarse aggregates(1st class brick aggregate, crushed stone aggregate, and recycled brick aggregate). Variables include type of aggregate and gradation of aggregate. Cement content was 300 kg/m3 and water-to-cement ratio was 0.33. Test items include void in aggregate, unit weight of aggregate, specific gravity of aggregate, compressive and tensile strength of pervious concrete at 28 days and permeability of water through the pervious concrete. The experimental results revealed that compressive strength as well as tensile strength of pervious concrete is inversely proportional to the permeability. Within the scope of this investigation, pervious concrete with compressive strength range from 650 to 1700 psi and permeability from 60 to 15 mm/sec can be made. The results clearly indicated that pervious concrete can be used on parking, walkways, and roads for light weight vehicles.
This paper presents a summary of some recent research closely associated with the sustainable de... more This paper presents a summary of some recent research closely associated with the sustainable development of concrete technology in Bangladesh. The research
projects include: (1) causes of deterioration of concrete structures in Bangladesh, (2) problems at construction sites that causes early deterioration of concrete structures in
Bangladesh, (3) the quality of various cement brands commonly used in Bangladesh, (4) the properties of concrete made with various aggregates commonly used in Bangladesh,
and (5) recycling of demolished concrete as coarse aggregate for new construction.
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Papers by Prof. Dr. Md. Tarek Uddin , Professor, CEE
projects include: (1) causes of deterioration of concrete structures in Bangladesh, (2) problems at construction sites that causes early deterioration of concrete structures in
Bangladesh, (3) the quality of various cement brands commonly used in Bangladesh, (4) the properties of concrete made with various aggregates commonly used in Bangladesh,
and (5) recycling of demolished concrete as coarse aggregate for new construction.
projects include: (1) causes of deterioration of concrete structures in Bangladesh, (2) problems at construction sites that causes early deterioration of concrete structures in
Bangladesh, (3) the quality of various cement brands commonly used in Bangladesh, (4) the properties of concrete made with various aggregates commonly used in Bangladesh,
and (5) recycling of demolished concrete as coarse aggregate for new construction.