矿粉混凝土早期抗裂性研究

THE RESISTANCE TO CRACKING OF CONCRETE WITH GROUND SLAG AT EARLY AGE

采用平板法研究了矿粉对混凝土早期抗裂性的影响。试验结果表明:强度越高,其早期抗裂性越差,同水胶比情况下,矿粉取代水泥,可明显改善混凝土的早期抗裂性;掺量越高,改善效果越明显;在同标号(R2 8)情况下,掺加矿粉对混凝土早期抗裂性无不利影响;在高标号(R2 8为 6 5～ 75MPa)、大掺量(≥ 35 % )情况下,对早期抗裂性有一定改善效果;掺加超细矿粉(≥ 730m2 kg)

The relationship between the addition and the fineness of slag and the resistance to cracking of concrete at early age was studied by using plain concrete specimen. The results show that the higher strength of concrete with ground slag, the weaker its resistance to cracking at early age. At the same water-binder ratio, the resistance to cracking of concrete at early age can be improved by ground slag replacement of cement; the more the addition of ground slag, the more obvious the effect of improvement. When the 28-day compressive strength of concrete is the same, there is no obvious difference to the resistance to cracking of concrete at early age by ground slag replacement of cement; when the 28-day compressive strength of the concrete with ground slag about 35% is 65～75MPa, the resistance to cracking of concrete at early age is able to be remarkably improved. When the fineness of ground slag is over 730m^2/kg, there is negative affect to the resistance to cracking of concrete at early age with ground slag.