High temperature resistance of boron active belite cement mortars containing fly ash

Boron allowing stability of reactive belite phase in clinker production enhances neutron shielding capability of cement. In the study, neutron attenuation factor of boron active belite cements at various fly ash introduction was theoretically revealed by comparing with an alternative low heat cement (portland composite cement). High temperature resistance of the cements with and without fly ash introduction was determined on standard mortar prisms at elevated temperatures up to 900 °C with regard to compressive strength and flexural strength. Neutron shielding performance of boron active belite cement was found almost 25 times higher than Portland composite cement. Fly ash introduction significantly reduced the neutron attenuation factor of boron active belite cement. High temperature resistance of boron active belite cement mortar was found lower than that of Portland composite cement mortar at 700 °C at later curing time. 10% fly ash introduction improved the high temperature performance of boron active belite cement mortar exposed to 900 °C. Residual compressive strength values of the mortars containing fly ash were between 16% and 28% after exposing 900 °C.