This work reports on some proper-ties and sintering behavior of B2O3 addition into fly ash in the range of 0 to 3 %. Cylindrical shaped samples were prepared by dry pressing uniaxially of fly ash containing B2O3 and as received fly ash. Samples were sintered in air between 850 degreesC and 1000 degreesC for I hour. Characterisation tests were employed including bulk density, apparent porosity, water absorption, thawing test, efflorescence test and compressive strength. The results revealed that the addition of B2O3 into fly ash resulted in considerably improved microstructure and physical properties.