Compressive Strength and Durability of FGD Gypsum-Based Mortars Blended with Ground Granulated Blast Furnace Slag

Abstract

One new flue gas desulfurization (FGD) gypsum-based binder is attempted in this article, which is made up of FGD gypsum, ground granulated blast furnace slag (GGBS) and ordinary Portland cement (OPC). Influences of raw materials, chemical activators, and curing conditions on the compressive strength of this new binder-based mortar, as well as its durability performances and microscopic characteristics, are investigated in consideration of utilizing FGD gypsum as much as possible. Results show that the compressive strength of this new binder-based mortar under normal curing conditions could increase along with GGBS dosages from three days to 90 days. The compressive strength of one selected mix proportion (FG-4550), which contains the highest dosage of FGD gypsum (45 wt.%), is much the same as those containing the highest dosage of GGBS. A better compressive strength of FG-4550 under normal curing conditions could be gained if the fineness of GGBS is improved. The activated effect of CaCl2 on the compressive strength of FG-4550 is superior to that of Ca(OH)2 under steam curing conditions. FG-4550 shows a good capacity for resistance to water, a low shrinkage ratio, but poor compressive strength after 30 freeze-thaw cycles. Based on the mineralogy of X-ray diffraction, the morphology of scanning electron microscopy and the pore diameter distributions of 1H nuclear magnetic resonance, the compressive strength of this FGD gypsum-based mortar mainly depends on clusters of ettringite.

Nano-Modified Vibrocentrifuged Concrete with Granulated Blast Slag: The Relationship between Mechanical Properties and Micro-Structural Analysis

“…The issue of the durability of concretes and mortars based on slag has also received much attention [26,30,[32][33][34][35][36]. At the same time, these characteristics of solutions with the addition of DHS as frost resistance [30] and resistance to chlorides [34], sulfates [33], and various acids [26,32] were studied.…”

“…At the same time, these characteristics of solutions with the addition of DHS as frost resistance [30] and resistance to chlorides [34], sulfates [33], and various acids [26,32] were studied. Moreover, the authors of many works consider the joint effect of GBFS and other additives (ash, limestone, gypsum, nanosilica) on the formation of the micro-and macrostructure of materials based on them and their physical and mechanical characteristics [10,28,30,[35][36][37][38].…”

Study and Characterization of Special Gypsum-Based Pastes for Their Use as a Replacement Material in Architectural Restoration and Construction

“…For some time, research has been being carried out into how to improve the mechanical properties of pastes so as to broaden the scope of their use. This fact has led to new mixes being studied in which natural and artificial fibers are added [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Usually, in the case of plasters or gypsum-based pastes, the way that this is achieved is by reinforcing them using fiberglass [ 17 , 18 , 19 ].…”

Supersulfated Cement Applied to Produce Lightweight Concrete

“…Modern methods of utilization of such wastes and by-products confirm the possibility of their use in various directions in construction, in particular, for producing low-energy non-burning binders such as supersulfated slag binders [ 6 , 7 ]. Thus, three main problems can be solved: making the production of binders based on secondary resources cheaper than the production of binders from natural raw materials [ 8 , 9 ]; ensuring environmental cleanliness and waste-free production [ 10 ]; obtaining binders with sufficiently high quality and with stability of the main characteristics [ 11 , 12 , 13 ]. …”

“…making the production of binders based on secondary resources cheaper than the production of binders from natural raw materials [ 8 , 9 ];…”