The Performance of Concrete Made with Secondary Products—Recycled Coarse Aggregates, Recycled Cement Mortar, and Fly Ash–Slag Mix

Abstract

The properties of cement concrete using waste materials—namely, recycled cement mortar, fly ash–slag, and recycled concrete aggregate—are presented. A treatment process for waste materials is proposed. Two research experiments were conducted. In the first, concretes were made with fly ash–slag mix (FAS) and recycled cement mortar (RCM) as additions. The most favorable content of the concrete additive in the form of RCM and FAS was determined experimentally, and their influence on the physical and mechanical properties of concrete was established. For this purpose, 10 test series were carried out according to the experimental plan. In the second study, concretes containing FAS–RCM and recycled concrete aggregate (RCA) as a 30% replacement of natural aggregate (NA) were prepared. The compressive strength, frost resistance, water absorption, volume density, thermal conductivity, and microstructure were researched. The test results show that the addition of FAS–RCM and RCA can produce composites with better physical and mechanical properties compared with concrete made only of natural raw materials and cement. The detailed results show that FAS–RCM can be a valuable substitute for cement and RCA as a replacement for natural aggregates. Compared with traditional cement concretes, concretes made of FAS, RCM, and RCA are characterized by a higher compressive strength: 7% higher in the case of 30% replacement of NA by RCA with the additional use of the innovative FAS–RCM additive as 30% of the cement mass.

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

“…The low dolomite intensity found in the gravels was not detected by TGA/DTA. Similar results were obtained in other research studies [ 12 , 30 , 76 ]. …”

“…RAC&D is usually of poorer quality than NA, which results in poorer properties of the resulting mixtures. This is due to RAC&D having adhered to the old mortar with lower density, higher porosity, lower crush resistance, higher water absorption value and weaker interfacial transition zones (ITZs) [ 5 , 12 , 30 , 31 ]. Therefore, the development of new techniques to improve the quality of RAC&D is on the rise [ 27 , 32 , 33 , 34 , 35 , 36 , 37 ], among which are those that improve the quality of RAC&D by using CO 2 (accelerated carbonation), which seems to be a very promising technology [ 38 , 39 , 40 , 41 ].…”

The Effect of Acanthocardia tuberculata Shell Powder as Filler on the Performance of Self-Compacting Mortar

“…Similar results have been found by Suescum-Morales et al [ 51 , 52 ]. For cement, four stages were observed: the first is attributed to moisture loss; the second to aluminates and silicates decomposition [ 20 ]; the third to portlandite [ 17 ]; and the fourth to calcium carbonate decomposition [ 13 , 53 ].…”

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

“…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].…”