The Effect of Bond Characteristics Between Steel Slag Fine Aggregate and Cement Paste on Mechanical Properties of Concre
- PDF / 772,515 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 16 Downloads / 181 Views
THE EFFECT OF BOND CHARACTERISTICS BETWEEN STEEL SLAG FINE AGGREGATE AND CEMENT PASTE ON MECHANICAL PROPERTIES OF CONCRETE AND MORTAR WANG YUJI Tongji University, Department of Materials Science and Engineering, Shanghai, China Received 10 November, 1987; refereed ABSTRACT The ordinary fine aggregate in concrete has been replaced by ground and sieved steel slag fine aggregate, treated and exposed to air for three months. Compared with concrete made from natural sand, properties such as compressive strength, flexural strength, elastic modulus, permeability and abrasion resistance are considerably improved. The improvement increases with a decrease in w/c ratio, an increase in curing time and an increase in the replacement weight of sand. These results are due to the fact that the steel slag contains some active minerals such as C 3 S, C2 S, C4 AF, etc., and shows favorable surface physical characteristics that improve the bond between steel slag particles and cement paste. The results of XRD, SEM and EPM microhardness showed that there are heavier concentration of ions, with finer crystals and a lower degree of CH orientation at the interfacial zone between steel slag particles and cement paste. The study also found small cementitious and fibrous C-S-H crystals growing from the fine aggregate, which are linked with hydrated products from cement paste making the bond and structural characteristic more favorable with cement. The steel slag fine aggregate is an active mineral similar to cement. The bond between the aggregate and cement paste is strengthened both physically and chemically. INTRODUCTION The purpose of this study was to explore replacement of ordinary fine aggregate in concrete by ground and sieved steel slag fine aggregate, treat the resulting material comparably and compare the compressive strength, flexural strength, elastic modulus, permeability and abrasion resistance of the product with concrete made with natural sand. In this experiment blast furnace cement 425 produced by the Shanghai Cement factory was used. Its physical properties are listed in Table I. The properties of ordinary aggregate and steel slag sand are given in Table II, and the chemical components of the steel slag are given in Table III. TEST RESULTS Table IV shows that the strength of slag sand mortar at different ages is higher than that of ordinary sand mortar, although they both have equal water contents and are produced under the same conditions. For a decrease in the water content from 0.44 to 0.30, the strength of the mortar at different ages increased. The trend of the gain in strength of slag sand mortar was similar to that of ordinary mortar. With an increase in the slag sand content, the rate of increase of the mortar strength increased. Table V shows that, when slag sand was used as a partial replacement for ordinary sand in concrete, the strength of concrete increased, and with the increase in slag content, the increase in strength became greater. This tendency was the same as that in mortar. Tables VI-VII show that use
Data Loading...
