Study of three distinct self-compacting concretes containing marble/granite powder and hooked-end steel fiber contents

Abstract

In this investigation distinctive self-compacting concretes (SCC) containing both marble + granite (MG) powder and hooked-end steel fibers (HESF) are investigated. A mixture of conventional SCC (reference), and other five samples containing MG and steel fiber (SF) contents are provided, i.e. 20MG, 20SF, 30MG + 10SF, 20SF and 30MG + 20 SF. Both the fresh and hardened properties of the modified self-compacting concretes are evaluated. Workability of the SCC samples represented by slump flow, L-box, V-funnel, J-ring and flowability T500 is examined. The properties of hardened state of the SCC samples at 7 and 28 days are also evaluated. Modulus of elasticity, water absortion, voids index (indicatig porosity), and specific mass are attained. Comparisons among specific strengths and consumptions of cement per compressive strengths are also provided. The SCC/30MG/10SF sample has a specific strength ∼50% higher than the conventional SCC sample. When a ratio involving porosity per cement consumption per tensile strength is evaluated, the SCC/30MG/10SF sample has this ratio ∼80% higher than the SCC reference. Additionally, the best result of consumption of cement (CC) per compressive strength (CS) (1.28x lower than the SCC reference) at 28 days is that of the SCC/30MG/10SF sample (5.03 kg/m3. MPa−1). This indicates that an environmentally friendly aspect associated with low relative cost, which is an important parameter to consider in future SCC mixture designing.

EIS Investigation of the Corrosion Behavior of Steel Bars Embedded into Modified Concretes with Eggshell Contents

“…The experimental correlations between the tensile (TS) and compressive strengths (CS) at 7 and 28 days of curing are shown in Figure 3. Although distinct modified concretes and cementitious materials were reported in previous studies [50,65,66], the obtained equations describing TS = k CS 0.5 are similar to those previously reported. When the ES portions (10 wt.%) replace cement and sand contents, slight decreasing trends were provided when compared with the CC sample.…”

“…This cement has finer characteristics and higher hydration (rapid) than other cements. The specific mass and unit mass were 3.12 g/cm 3 and 1.03 g/cm 3 as also previously reported [49,50]. Fine and coarse aggregates were natural quartzite sand and basalt gravel #0 (size between 4.75 and 9.5 mm).…”

“…Fine and coarse aggregates were natural quartzite sand and basalt gravel #0 (size between 4.75 and 9.5 mm). This was adopted based on previous investigations [49,50] considering the cover area between particles and steel rebar embedded. The sand proportions were kept at 100 (±5) • C for 24 h before the mixture procedure.…”

“…The fresh state properties of the distinct SCC samples were determined using a Brazilian standard ABNT NBR 15823:2017 [49,50]. According to ASTM C1611-18 [49,50], the traditional slump measurements were performed.…”

“…The fresh state properties of the distinct SCC samples were determined using a Brazilian standard ABNT NBR 15823:2017 [49,50]. According to ASTM C1611-18 [49,50], the traditional slump measurements were performed. These procedures were conducted in order to measure the ability of the concrete to pass through obstacles and to flow under certain conditions [11].…”