The fracture response of blended formulations containing limestone powder: Evaluations using two-parameter fracture model and digital image correlation

Fracture process zone and tensile behavior of blended binders containing limestone powder

“…Limestone has also been observed to chemically combine with aluminum-provisioning materials such as fly ash or metakaolin to produce carboaluminate phases that improve the material microstructure and the properties [8,9]. This has resulted in methodologies that facilitate an increase in the limestone content in concretes beyond the ASTM compliance limit of 15%, especially in ternary binders which show beneficial changes in porosity and compressive/flexural strengths [3,10].…”

“…A recent study investigated the fracture properties of binary and ternary limestone blended matrices using notched beams in three-point bending and a two-parameter fracture model (TPFM) [10], and demonstrated that these matrices are more crack-tolerant. The crack-tolerance of such quasi-brittle materials is greatly influenced by the nature of stress transfer in the fracture process zone (FPZ).…”

“…While several experimental techniques such as high speed photography [12], acoustic emission [13][14][15], scanning electron microscopy (SEM) [16][17][18][19], and laser-speckle interferometry [20,21] have been used to investigate FPZ in concretes, this study employs a non-contact digital image correlation (DIC)-based speckle-tracking method [10,[22][23][24][25][26][27][28] to assess the surface displacements and strains, and thus the width of the FPZ. The presence of soft(er) limestone particles and ductile clay phase (from metakaolin), which improves the fracture performance of multiple-material binders through improved inelastic energy dissipation [10], influences the FPZ, which is explored in detail.…”

“…The presence of soft(er) limestone particles and ductile clay phase (from metakaolin), which improves the fracture performance of multiple-material binders through improved inelastic energy dissipation [10], influences the FPZ, which is explored in detail. The tensile strengths and the ultimate tensile strains of these systems are extracted via inverse analysis of the flexural load-deflection data using an analytical tension model [29][30][31][32].…”

Experimental Evaluation of Mechanical Properties and Fracture Behavior of Carbon Fiber Reinforced High Strength Concrete

“…An elastically equivalent fracture toughness, K IC , is one of the most important parameters for fracture characterization of cementitious systems along with the critical crack tip opening displacement (CTOD C ) which is a measure of the bridging interlock capability of the microstructure and indicates the limit beyond which unstable crack propagation begins [23,24]. Table 4 reports these two major fracture parameters which was derived using the TPFM for all the mixtures studied here.…”