Title:
Properties of Concrete Incorporating Low Quantity of Cement and High Volumes of Ground Granulated Slag
Author(s):
V. Sivasundaram and V. M. Malhotra
Publication:
Materials Journal
Volume:
89
Issue:
6
Appears on pages(s):
554-563
Keywords:
adiabatic conditions; air entrainment; blast furnace slag; chlorides; compressive strength; drying shrinkage; flexural strength; workability; modulus of elasticity; setting (hardening); sulfate resistance; Materials Research
DOI:
10.14359/4027
Date:
11/1/1992
Abstract:
Presents the results of a study carried out on superplasticized, air- entrained concretes incorporating low quantities of ASTM Type I cement and high volumes of ground granulated blast furnace slag. The slag was obtained from a source in northern Ontario. Three series of concrete mixtures were made with cement contents of 100, 125, and 150 kg/m 3 (169, 211, and 253 lb/yd 3). The proportion of the slag in the concretes ranged from 50 to 75 percent of the total cementitious materials. The water content of the concretes was kept constant at 115 kg/m 3 (194 lb/yd 3), and high slumps were achieved by means of a superplasticizer. The properties of the fresh concretes, including the time of setting, were determined, and a large number of concrete specimens were subjected to the determination of autogenous temperature rise, compressive and flexural strengths, Young's modulus of elasticity, drying shrinkage, resistance to chloride-ion penetration, and sulfate resistance. The workability of the concretes decreased with increasing slag content, and as the water-to- cementitious materials ratio was reduced below 0.30, the workability decreased substantially. The autogenous temperature rise in the concrete was suppressed by the incorporation of high volumes of slag. A maximum temperature rise of 5.5 C was measured in 152 by 305-mm cylinders of concrete incorporating 124 kg/m 3 (209 lb/yd 3) of cement and 288 kg/m 3 (485 lb/yd 3) of slag. From the age of 7 days on, the high-volume slag concretes investigated achieved compressive strengths similar to comparable control concretes. Most had 91-day strengths exceeding 50 MPa. At the cementitious materials level of 300 kg/m 3 (506 lb/yd 3), the high-volume slag concretes exhibited better strength development at later ages than the control concrete. The strength evelopment of the slag concretes with 250 kg/m 3 (421 lb/yd 3) of cementitiou materials was low, with 91-day strengths of the order of 25 Mpa. The 41-day flexural strengths of most of the slag concretes, at about 8 Mpa, were higher than that of the control concretes. Also, the 28-day Young's modulus of elasticity of most of the slag concretes were quite high, at 42 Gpa. The slag concretes' resistance to chloride-ion penetration was exceptionally high compared to that of the control concretes, and this resistance, measured in terms of electrical charge in coulombs, ranged from 174 to 383 for most slag concretes. The drying shrinkage strains of the slag concretes measured so far are comparable to that of the control concretes.