Durability Behavior of Mortars Containing Perlite Tailings: Alkali–Silicate Reaction Viewpoint

Abstract

Tailing incorporation into mortars has been the subject of much research in recent years. Despite this, most of these studies did not investigate the harmful effects resulting from the exposure of such mortars to an environment containing aggressive agents. This work investigated the effects of perlite tailing addition into mortars containing cement CP V-ARI MAX and hydrated lime. The raw materials were subjected to chemical characterization (X-ray fluorescence (XRF)) and mineralogical (X-ray diffraction (XRD)), while the samples immersed in 1 N NaOH solution were characterized by XRD, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and compression strength (CS). The results showed the harmful effects of incorporating perlite tailings into the mortar investigated. Such a degradation was proven by linear expansion and compressive strength experiments accomplished in the samples after the test of resistance to an alkali–silicate reaction.

Resistance to the alkali-aggregate reaction of sustainable mortars produced with scheelite tailings in replacing natural sand aggregates

“…Some authors (Evaristo De Oliveira Neto et al, 2021;Munhoz et al, 2021) have identified the presence of this amorphous alkaline gel via microstructure analysis.…”

“…It is known that the OHcontained in the mortar's pores (from immersion in the aggressive environment of NaOH) comes into contact with the mortar's reactive minerals. These, in turn, can react with alkalis present in Portland cement, originating the alkali-silicate reaction (Evaristo De Oliveira Neto et al, 2021). Figure 6 shows the image obtained by Scanning Electron Microscopy using backscattered electrons (SEM-BSE), in which it was possible to identify the pores of the samples, the aggregates (Scheelite tailings), and the hydration products of the cement paste, such as calcium hydroxide (C-H), hydrated calcium silicate (C-S-H), identified in the circled regions of the image.…”

Incorporation of Bentonite Mining Waste in Ceramic Formulations for the Manufacturing of Porcelain Stoneware

“…Numerous mining residues have been successfully reused as an alternative raw material to manufacture sustainable materials, such as ceramic refractories [17,18], ceramic tiles [19][20][21], bricks [22][23][24][25][26], roof tiles [27][28][29][30], porous ceramics [31][32][33][34], and sanitary ware [35], among others. Various mining waste types stand out, including iron ore tailings [36][37][38], kaolin waste [39,40], scheelite [41,42], ornamental rock waste [43,44], perlite waste [45][46][47][48], etc. In a recent study, Araújo et al [49] evaluated the potential for reusing waste from bentonite mining as adsorbents for treating water contaminated with cationic dyes.…”