Strength analysis of concrete (300/20) with superplasticizer

Admixtures are used in concrete to obtain some specific properties to enhance the performance of concrete. In this research concrete of a specific grade (300/20) with a superplaticizer Ha Ba has been selected to enhance the reliability on the use of admixture in concreting. In the introduction part of the research properties of superplaticizer are discussed while later the technical data of Ha Be and result of different test on concrete are discussed. Initially materials / ingredients of concrete (300/20) are specified and correction for moisture have been made for 1 cum. A total of six design batches are selected to prepare a total of 36 cube of standard size (150mm x 150mm 150mm). To know the workability, the slump have been conducted at six stages i.e. initial, at 30 minutes, 45 minutes, 60 minutes, 75 minutes and at 90 minutes. The study shows that the concrete with the use of this specific superplasticizer (Ha Be) get the desired workability (slump value 150+25 mm) at 60 minutes, and it is concluded that such superplasticizer are recommended where transportation of concrete required 60 minutes. Since concrete gain a significant strength at seven days and remaining strength is gained at 28 day, therefore 18 cubes have been crushed at an age of 7 days, while remaining 18 have been crushed at an age of 28 days. These strength especially the 28th day strength (average value = 53 Mpa) has been compared with the required one (46 Mpa) and was found satisfactory. The densities of all the 36 cubes were also computed at two stages to compare it with the required density (2400 kg/m3). Both the calculated densities at 7 days for 18 cubes and at 28 days for 18 cubes was compared and found satisfactory. At the end it is concluded that if any superplasticizer is required to get some specific properties it can be use confidently since it not affected on the strength at all. Although since the research is only focusing on the strength at upto 28 days therefore it is also required to study the behavior of concrete at later stages to see there is any adverse effect in concrete due to the use of any superplasticizer