Other Research – Reports

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Browsing Other Research – Reports by Subject "Civil Engineering-Research Report"

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    Irrigation reservoir performance : a case study of Lunugamvehera reservoir
    Wijesekera, NTS
    Lunugamwehera reservoir is a large water body with a storage capacity of 170,000 Act, constructed under the Kirindi Oya Irrigation and Settlement Project (Figure 1). The Kirindi Oya development project was commissioned in March 1986. Lunugamwehera reservoir under this project is located in the relatively dry zone in South-East quadrant of Sri Lanka at a distance of approximately 260km from Colombo. Lunugamwehera at full capacity spreads over an area of 7450 acres. Lunugamwehera reservoir which is constructed across Kirindi Oya has a drainage area of 353 square miles. Drainage basin of Kirindi Oya is narrow and extends from Bandarawela at 6350 ft MSL for a distance of 75 miles to the sea at Kirinda. Total watershed area of Kirindi Oya is 455 sq. miles (Dharmasena 1986). The Lunugamwehera reservoir consists of a left bank and right bank canal system. It provides water to about 25 small villages with 5000 families located at close proximity. There is a drinking water supply scheme to serve people in the region and water supply is extended to an animal and diary development project to develop livestock resource. Other than the above, approximately 10,500 acres in Tissa region receives water through a network of 5 old tank network downstream of the Lunugamwehera reservoir.
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    Prediction of compressive strength of concrete: final report
    Nanayakkara, SMA
    This report presents a method of predicting compressive strength of concrete. The approach is based on experimental investigation of compressive strength development of grade 20, 25, 30 and 50 concrete with three different brands of cement. The criterion used for the prediction of strength involves the determination of equivalent age of concrete, which depends on curing temperature and age of concrete. It was found that the compressive strength of concrete varies linearly with respect to the logarithmic value of the equivalent age. Furthermore, it was observed that the rate of change of strength with respect to logarithmic value of equivalent age varies non-linearly with respect to w/c ratio. This variation was not the same for all brands of cement tested. Expressions were derived for compressive strength for each brand of cement with respect to w/c ratio, age and curing temperature. Based on these expressions, a chart was developed to establish the relationship between strength and w/c ratio for a range of strength grades. This chart can be used in mix design of concrete using local materials. Since it was not possible to develop a unique expression for the prediction of compressive strength of concrete in terms of mix design parameters like w/c for any cement brand, the identified behavior of the strength development of concrete with respect to equivalent age was used in predicting strength of concrete. In the proposed method, the 28-day strength can be predicted with strength results at two ages such as 1-day and 3-day strengths. A good agreement with the predicted and experimental results have been obtained not only for test results obtained under this study but also for other published test data.