چكيده به لاتين
Abstract:
The interfacial transition zone (ITZ) between cement paste and aggregate has a great role in determining the quality properties of mortar and concrete. Studies have confirmed different microscopic features for interfacial transition zone compared to cement paste that are cause of compressive strength loss in cement mortar and concrete. In this research, the effects of using granulated phosphorus slag as a reactive sand instead of standard sand in alkali-activated phosphorus slag cement mortar on compressive strength and ITZ microstructure have been studied. Based on the results, use of granulated phosphorus slag as reactive sand increases the 3-, 7-, 28-, and 60-day compressive strength of mortar from 10, 25, 42, and 50 MPa to 12, 30, 45 and 57 MPa, respectively, at the same water-to-cement ratio of 0.54. The SEM studies confirmed that increases achieved in compressive strength were mainly due to improvements brought about in ITZ microstructure and in control mortar containing standard sand, there existed a weak and more porous ITZ separating the cement paste from sand surface. In fact, use of granulated phosphorus slag as a reactive sand in alkali-activated phosphorus slag mortar forms a noticeably more uniform and compact ITZ and this increases the mechanical strength of mortar, in addition to helping in reducing environmental pollutions due to phosphorus slag disposal and conserving natural sand resources.
Keywords: Alkali-activated phosphorus slag, Natural standard sand, Transition zone, Compressive strength
