Title:
Role of Superplasticizers and Slag for Producing High Performance Concrete
Author(s):
R. N. Swamy, M. Sakai, and N. Nakamura
Publication:
Symposium Paper
Volume:
148
Issue:
Appears on pages(s):
1-26
Keywords:
blast furnace slag; bleeding (concrete); durability; high-performance concretes; permeability; porosity; setting (hardening); slags; strength; superplasticizers; water-reducing agents; Materials Research
DOI:
10.14359/4100
Date:
9/1/1994
Abstract:
Presents a detailed investigation of the role and effectiveness of ground granulated blast furnace slag and a high-range water reducer (HRWR) on the quality of concrete in terms of bleeding, setting times, heat evolution, strength development, and pore structure. The tests were carried out in two parts. In the first, a slag of normal fineness was used, and both the replacement level and water-binder ratio were varied. It was found that both the slag and HRWR acted as set retarders in terms of setting times and heat evolution. The water-binder ratio was the predominant factor affecting the rate of bleeding. The presence of slag, on the other hand, caused low-early strength and slow strength development, but had significant beneficial influence on the total pore volume and pore size distribution. In the second part, fineness of slag was varied from 453 to 1160 m 2/kg and the replacement level was kept constant at 50 percent. It was then possible to obtain compressive strength in excess of 30 MPa at 3 days and 100 MPa at 28 days, with substantial reductions in total porosity and water permeability. The bleeding rate was also reduced and the setting times also improved. The overall conclusion of this study is that a judicious combination of HRWR and slag fineness can lead to a very effective synergic interaction to produce concretes of high strength, high modulus, and low porosity.