Development of nominal concrete mixes for medium strength concrete : coursework submited to the department of civil engineering

Abstract

In BS 8110 : Parti : 1985, the improved durability of concrete was achieved by using mixes with higher strength such as grades 25 and 30. However, volume batched nominal mix of 1:2:4 (20 mm ) is still used in many construction sites in Sri Lanka. This could be an undesirable situation which should be corrected with both short term and long term solutions. In this research, a cost effective short term solution is suggested to obtain grades 25 and 30 concretes based on a detailed experimental programme. The findings of questionnaire survey has revealed that many engineers in Sri Lanka are willing to adopt such quality improvements for concrete.