Characteristics of Different Type of Coarse Aggregate on Properties of High Performance Concrete

The weakest links of conventional cement concrete is often occurred at the transition zone around coarse aggregate particles and the bulk of the compressive load is also borne by the cement paste. However, in special concrete such as High Strength Concrete (HSC) and High Performance Concrete (HPC) where, the water/cement ratio is low and high content of cement constitute their characteristics, the bulk compressive load is borne by the aggregate. Therefore, the failure in such concrete is mostly through the aggregate. This study discussed the characteristics of different type of coarse aggregate with distinct size range, 20-14mm and 10-5mm on properties of high performance concrete. In this project, investigation such as Slump test and Unit weight were carried out on fresh properties, and also compressive strength and water absorption on hardened properties, in which, readings were taken at curing days of 7 days, 14 days, and 28 days. The water to cement ratio used is 0.35, 1% super plasticizer of  Conplast SP-430 were added, and the dosage of meta kaolin added was  0%, 7.5% and 15%. The HPC mix, grade M40concrete is designed as per ACI method. The result of the study indicated that the compressive strength increases with an increase in percentage of Metakaolin between 0% to 15% replacements. Basalt-mixed concrete gives higher compressive strength, followed by gneiss-mixed concrete, then granite-mixed concrete. It was also discovered that larger aggregate sizes (20mm-14mm) gives high compressive strength than smaller sizes (5mm-10mm). Therefore for optimum performance up to 15% replacement of Metakaolin can be used with 20mm-14mm sizes of basalt aggregate

Performance Evaluation of Tamarindus Indica Seeds Powder in the Treatment of Dye Wastewater

A large amount of dye wastewater is generated after the local dyeing process. It contains high concentrations of organic and inorganic contaminants. Furthermore, the composition of the wastewater varies according to the type and number of textiles and the water requirements of the process. Hence, its treatment before discharge is necessary to protect the environment. This study investigated the use and effectiveness of Tamarindus indica seeds powder from agricultural waste for removing some recalcitrant target compounds in the dye wastewater. A batch test was performed to examine the use of this adsorbent as a potential replacement for the advanced treatment methods. Varying adsorbent dosages determined the maximum adsorption capacity at 30, 35, 40, 45, and 50 g and at 24, 48, 72, 96 and 120 hr reaction times. The optimum dosage, reaction time and percentage removal of various parameters were found to be; Turbidity (no significant effect), TDS (40 g/l, 72 hrs, 54.42%), EC (35 g/l, 72 hrs, 4.46%), Phosphate (35 g/l, 24 hrs, 38.49 %), Total suspended solid (no significant effect), Nitrate (30 g/l, 96 hrs, 15.26%), COD (no considerable impact) and BOD (30 g/l, 48 hrs, 63.38%) respectively. The results showed that adsorption efficiency increased with decreased adsorbent dosage, even at different reaction times. Hence, low-cost adsorbents such as Tamarindus indica seeds can treat dye waste water to a certain level for safe disposal