Microstructure, Durability and Mechanical Properties of Mortars Prepared Using Ternary Binders with Addition of Slag, Fly Ash and Limestone

Abstract

In order to improve the contribution to sustainability of cement production, several strategies have been developed, such as the incorporation of additions as clinker replacement. Regarding the production of commercial cements with additions, those made with binary binders are mostly produced. However, the use of ternary binders for manufacturing commercial cements is still very low, at least in Spain, and they could also be an adequate solution for producing eco-friendly cements. The objective of this research is to study the effects in the long term produced by ternary binders which combine the additions of blast furnace slag, fly ash and limestone in the microstructure, durability and mechanical performance of mortars, compared to mortars without additions and mortars made with binary binders. The ternary and binary binders accomplished the prescriptions for a cement type CEM II/B. The microstructure was characterized using mercury intrusion porosimetry, electrical resistivity and differential thermal analysis. Absorption after immersion, diffusion coefficient, mechanical strengths and ultrasonic pulse velocity were studied. The best performance was noted for ternary binder with both slag and fly ash, probably produced by the synergetic effects of slag hydration and fly ash pozzolanic reactions. These effects were more noticeable regarding the compressive strength.

Long-Term Behavior Related to Water Ingress in Mortars Which Combine Expanded and Natural Cork Lightweight Aggregates and Eco-Friendly Cements

“…Moreover, the reduction with maturing age in the volume of gel and capillary pores for most of the series analyzed would be due to the progress of slag and clinker hydration [22,52] and the pozzolanic reactions of fly ash [17,18], which would produce a progressive formation of solid phases, partially closing the microstructure in the long term. The higher volume of finer pores generally observed for series with fly ash and slag, regardless of the aggregate used, could be related to the reactivity of these additions, and this result would be in keeping with other authors [17,18,[53][54][55]. In the case of slag, it has hydraulic activity [22,52,56], so it is capable to react directly with the setting water, forming new solids, which would fill the existing pores, thus reducing the volume of larger voids in the microstructure.…”

“…The results of the absorption after immersion, previously described, showed coincidences with those obtained in the study of the gel and capillary pores in the microstructure. The decrease with maturing age would agree with the reduction in the total volume of gel and capillary pores observed with mercury intrusion porosimetry, which was explained due to the formation of solids as products of hydration reactions of clinker and slag [53][54][55] and pozzolanic reactions of fly ash [17,18]. Furthermore, the higher values of the absorption after immersion noted for series with expanded cork compared to those with expanded clay and natural cork may be related to the higher volume of large capillary pores observed in mortars with expanded cork.…”

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].…”

Special Issue on “Recycling Waste in Construction Materials, Volume II”

“…Moreover, Bih Numfor et al [3] used pulverized low-density polyethylene (LDPE) waste as a source to reinforce and improve the compressive strength and reduce the water absorption of geopolymer ceramics formulated from metaclay and metakaolin aluminasilicates. Another study was that of Ibáñez-Gonsálvez et al [4]. They studied the effects produced in the long term by ternary binders.…”