Study of the Failure Mechanism of Mortar Rubble Using Digital Image Correlation, Acoustic Emission and Scanning Electron Microscopy

Abstract

This paper describes an extensive experimental study of the compressive failure of different types of aggregates and the influence of aggregate type on the interfacial properties of mortars. Interfacial debonding was the main failure mode of mortar rubbles. The interlocking strength of aggregate and mortar strongly affected the compressive strength of materials. When basalt was used as the aggregate, I-II composite failure of the deflection crack occurred as well as interfacial debonding. The highest instantaneous AE energy of the granite mortar rubble was 1349 mV·ms, which was 4.1 times greater than that of the basalt mortar rubble (326 mV·ms). Acoustic emissions of mortar rubble were strongest in the 150–220 kHz range and gave an early warning of the damage load at high frequencies (160–320 kHz). The C-S-H gel formed by the hydration reaction adhered to the aggregate pores and exhibited a “root pile” effect that improved the bonding performance of the interfacial zone. The interfacial porosity of the basalt, granite and limestone mortar rubble was 21.29%, 18.70% and 30.0%, respectively. The limestone interface has a large porosity, the fractal cones was small (1.19), and there was an obvious sidewall effect, but the interfacial strength was weak. The pore structure had a significant effect on the interfacial bond strength. This multi-faceted analysis truly reflected the state and evolution of the damage of mortar rubbles, and the results were very effective for determining the mechanical mode of damage of mortar rubbles.

Examination of Damage Evolution in Slurry Masonry Schist Subjected to Biaxial Compressive Stresses

“…The parameters of the DIC speckle deformation measurement system were configured as shown in Table 5. The testing standards were referenced from the study on the failure mechanism of slurry masonry schist conducted by Li et al [13].…”

“…The experiment employed porous basalt as the coarse aggregate for the slurry schist, utilizing Chinese standard (GB 175-99) PO.42.5 ordinary Portland cement as the cement [13] and medium sand as the fine aggregate. Since the grain sizes of the schist specimens were larger than 150 mm, the slurry schist structure was scaled down by a ratio of 1:2 according to similarity theory; hence, the grain size of the schist was set to 60~90 mm.…”

“…Caliskan et al [12] reported that the bonding behavior between schist and mortar is mechanical rather than chemical in nature. Li et al [13] concluded that the damage in slurry masonry schist structures occurs mainly in the form of interfacial debonding damage and that the interfacial transition zone (ITZ) between schist and mortar is the weakest place. Furthermore, several scholars have studied the debonding behavior of the interface transition zone between schist and mortar [14,15].…”

Comparison of locally manufactured composite tile adhesive using waste material with imported tile adhesive

“…The "root pile" effect of the C-S-H gel, formed by the cement-AAC waste's hydration reaction to the fine aggregate pores, enhanced the bonding capability. Figure 6 demonstrates how the strength was mainly responsible for the strength between the mortar and aggregate [27].…”

Experimental Study on the Dynamic Fracture Characteristics of Mortar–Rock Interface Zones with Different Interface Inclinations and Shapes

“…Recently, some scholars have investigated the interface properties in concrete materials from experimental and analytical perspectives [15][16][17][18][19][20][21]. Kaplan [22] was the first to introduce the concept of fracture mechanics in the study of crack extension.…”