Effect of Coarse Aggregate Grading on Mechanical Parameters and Fracture Toughness of Limestone Concrete

Abstract

This work presents a discussion of the basic properties of broken mineral limestone aggregates with the specification of the properties affecting the fracture toughness of concretes made with these aggregates. To determine the influence of the grain-size distribution of coarse aggregates for each concrete series, two types of aggregate grain were used, with maximum grain sizes of 8 mm (series of concrete L1) and 16 mm (series of concrete L2). Fracture-toughness tests were carried out using mode I fractures in accordance with the RILEM Draft recommendations, TC-89 FMT. During the experiments the critical stress-intensity factor (KIcS) and crack-tip-opening displacements (CTODc) were determined. The main mechanical parameters, i.e., the compressive strength (fcm) and splitting tensile strength (fctm), were also assessed. Based on the obtained results, it was found that the grain-size distribution of the limestone aggregate influenced the concrete’s mechanical and fracture-mechanics parameters. The obtained results showed that the series-L2 concrete had higher strength and fracture-mechanics parameters, i.e.,: fcm—45.06 MPa, fctm—3.03 MPa, KIcS—1.22 MN/m3/2, and CTODc —12.87 m10−6. However, the concrete with a maximum grain size of 8 mm (series of concrete L1) presented lower values for all the analyzed parameters, i.e.,: fcm—39.17 MPa, fctm—2.57 MPa, KIcS—0.99 MN/m3/2, and CTODc —10.02 m10−6. The main reason for the lower fracture toughness of the concretes with smaller grain sizes was the weakness of the ITZ in this composite compared to the ITZ in the concrete with a maximum grain size of 16 mm. The obtained test results can help designers, concrete producers, and contractors working with concrete structures to ensure the more conscious composition of concrete mixes with limestone aggregates, as well as to produce precise forecasts for the operational properties of concrete composites containing fillers obtained from carbonate rocks.

A Quasi-2D Exploration of Mixed-Mode Fracture Propagation in Concrete Semi-Circular Chevron-Notched Disks

“…Second, the uncertainty analysis regarding those issues worth further pursuing with quantitative analysis, as comprehensively examining variou SCB test settings in former studies [31]. Third, as this study narrowed down the researc focus merely on mixed-mode fracturing (types I and II) for SCB tests on chevron notc disks having sharp tips instead of a straight-through notch, many other influencing fa tors, such as the effects of aggregate size [42], cyclic loading [43], another mixed-mod fracturing (types I and III) [44], etc., have not been sufficiently considered at the initi However, those criteria are applicable mostly for homogeneous brittle materials such as glass, rock, and concrete without reinforcement. Razmi and Mirsayar [40] and Karimzadeh, et al [41] used SCB tests to investigate mixed-mode (types I and II) fractures in concrete SCCND specimens reinforced with fibers.…”

“…Second, the uncertainty analysis regarding those issues is worth further pursuing with quantitative analysis, as comprehensively examining various SCB test settings in former studies [31]. Third, as this study narrowed down the research focus merely on mixed-mode fracturing (types I and II) for SCB tests on chevron notch disks having sharp tips instead of a straight-through notch, many other influencing factors, such as the effects of aggregate size [42], cyclic loading [43], another mixed-model fracturing (types I and III) [44], etc., have not been sufficiently considered at the initial stage of this study and should, therefore, be further investigated in the future works. Last, the other numerical method, the discrete element method (DEM) [45], can be additionally involved in future numerical modelling mixed-mode fracturing behavior to explore the dependence of different numerical methods.…”

Elements of Metamorphic Rocks (Marble and Quartzite) of Bukit Cinta Gunung Gajah, Klaten

“…The type of rock found in the observations is limestone sedimentary rock. Limestone can be used for building mixes, road hardening, and house foundations (Golewski, 2023). Sedimentary rocks generally have pores to store water.…”

Examination of water absorption of low volume fly ash concrete (LVFAC) under water immersion conditions

“…The basic binder in concrete is ordinary Portland cement (OPC), the production of which is unfortunately the main contributor to greenhouse gas (GHG) emissions, mainly CO 2 , associated with global warming and climate change on Earth [18][19][20][21][22][23]. It is estimated that the amount of CO 2 produced during the burning of the Portland clinker, from which OPC is obtained after grinding, is from 8% to even 10% of the global annual emission of this harmful oxide [24][25][26].…”