Fengqing Zhao

Preparation of a new polymer-modified adhesive mortar using fine iron tailings as aggregate

In this paper, a new polymer-modified adhesive mortar is prepared using the fine iron tailings, eco-cement, redispersible latex powder, additives, and water. In our study, the fine iron tailings are used to replace the natural river sand as the mortar aggregate and the optimal process conditions are determined by the orthogonal experiment. The obtained results are shown as follows: The ratios of cement–sand and polymer–cement are 1:2.5 and 4%, respectively, with the aggregate modulus 0.81 and water reducing agent 0.5% (cement-based). The properties of the polymer-modified adhesive mortar obtained under the optimal process conditions conform to JC/T 547-2005 (China Professional Standard: Ceramic Tile Adhesive). Moreover, the microstructure of the polymer-modified adhesive mortar is studied and discussed. The results show that the network formed by the intertwined polymer film can prevent the merger of micro-cracks and improve the adhesive mortars’ overall cohesion. Therefore, adding polymer to the adhesive mortar can improve its failure stress and enhance its bonding strength.

Utilization of High Carbon Fly Ash and Coal Gangue in Blended Cement: A Case Study

The purpose of this work is to present an effective alternative to combined use of high carbon fly ash (HCFA) and coal gangue. HCFA, coal gangue, together with some additives and water, were mixed, dried, and clacinated at 700degC~900degC to produce a cement admixture (FGA),which is used to produce environment friendly cementing material by mixing and co- grinding with granulated blast-furnace slag (GBFS) and alkali activator. The optimized formulation of the cementing material for Strength Grade 42.5 (GB12958-1999) was obtained with the aid of orthogonal array technique: FGA-47%, GBFS-47%, activator-6%. The hydration products, studied by SEM and XRD, are mainly ettringite and C-S-H (I).