| Author | Azhar, Salman |
| Call Number | AIT Thesis no.ST-98-07 |
| Subject(s) | Concrete--Testing
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Dry premixed concrete is a relatively new product in the concrete industry. It contains a mixture of cement, aggregates and admixtures, all packed in a bag that can be mixed with water to produce concrete of a given strength and workability. The dry premixed concrete available in the market is of low strength (250 ksc), which limits its use in large construction projects where usually high strength and high workability is required. This experimental study was conducted to develop high performance dry premixed concrete, which could give both high strength and economy than other concrete production methods namely in-situ and ready-mixed concrete production. The target compressive strength was 600 ksc at 28 days for normal workability. The parent materials were selected from Pakistan and Thailand based on the criterion of identical properties. Two types of coarse aggregate namely limestone and andesite were used in two maximum sizes of 10 mm and 20 mm. Fly ash was incorporated as cement replacement material in 20% and 30% amount by weight to reduce the cost. Silica fume was added as 10% by weight of cement to increase the early strength. All the mixtures were produced at three workability levels and tested for compressive strength at 3, 7, 28 and 56 days. Test results showed that dry concrete containing limestone aggregates of 10 mm maximum size and 20% fly ash replacement gave the desired performance for strength and workability. Cost analysis indicated that it was 18% cheaper than ready-mixed concrete but 10% more expensive than in-situ concrete. However, this high performance dry concrete takes only one-third of the time to produce the same quantity as compared to in-situ concrete. This is beneficial in improving the productivity at site and can reduce the overall cost of the project by cutting indirect costs. The selected mix was also tested for flexural strength and modulus of elasticity and found to be satisfactory. |
| Year | 1998 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul; |
| Examination Committee(s) | Ogunlana, Stephen O.;Kishi, Toshiharu; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |