Copper slag concrete admixed with polypropylene fibres

Projektiranje održivog betona postao je glavni zahtjev u današnjoj industriji betona. U ovom radu je prikazan i analiziran dio opsežnog istraživačkog projekta koji je usmjeren na istraživanje mogućnosti korištenja bakrene zgure (eng. copper slag - CS) i polipropilenskih (PP) vlakana (eng. polypropylene fibre). Ispitivanja su provedena s ciljem utvrđivanja obradljivosti, gustoće, tlačne čvrstoće, vlačne čvrstoće i svojstava mikrostrukture betona te granične nosivosti armiranobetonskih greda izrađenih od takvog betona.A sustainable concrete design has become an imperative requirement for the present-day concrete industry. A part of an extensive research project aimed at studying possibilities for using copper slag (CS) and polypropylene (PP) fibres in concrete is presented and analysed. Measurements were conducted to investigate the workability, density, compressive strength, tensile strength, and micro-structural properties of concrete, as well as the ultimate load carrying capacity of reinforced-concrete beams made of this type of concrete

Impact Resistance of Polypropylene Fibre-Reinforced Alkali–Activated Copper Slag Concrete

Copper slag (CS) is produced during the smelting process to separate copper from copper ore. The object of the experimental research is to find the optimum percentage of CS and PPF volume fraction when CS replaces fine aggregate, and PPF volume fraction when subjected to impact loading. Copper slag was incorporated as 20%, 40%, 60%, 80% and 100% with PPF of 0.2–0.8% with 0.2% increment. The number of blows on failure of the specimen increases as the fibre volume increases. In addition, the energy absorption of composite concrete is higher than that of ordinary concrete. Concrete with up to 40% CS and 0.6% PPF volume shows a 111.72% increase in the number of blows for failure as compared to the control specimen. The impact resistance at failure was predicted by regression analysis, and very high regression coefficients of 0.93, 0.98 and 0.98 were obtained respectively at 7-, 14- and 28-days curing. In addition to regression analysis, a two-parameter Weibull distribution analysis was used to obtain reliable data on the number of blows at first cracking and eventual failure. The energy absorption at 28-day curing period is 1485.81 Nm which is 284% higher than the control mix. Based on the findings, it can be inferred that adding CS up to 60% densifies the microstructure due to its pozzolanic activity, while polypropylene fibre acts as a micro reinforcement, increasing the number of blows

Performance of recycled Bakelite plastic waste as eco-friendly aggregate in the concrete beams

The use of plastic waste as a partial or complete replacement for coarse aggregate in concrete mixtures has been studied in recent years. However, the quality and quantity of coarse plastic waste particles have been a challenge. This study aims to investigate the mechanical performance of concrete with Bakelite plastic waste as a partial replacement for coarse aggregate. Six different concrete mixtures with various Bakelite dosages, ranging from 0 % to 10 %, were tested. The results indicate that the addition of Bakelite plastic alters the behaviour of the concrete and reduces compressive and flexural strengths at lower dosages. The inclusion of Bakelite waste in concrete mixtures generally leads to a decrease in compressive and split tensile strength, with the exception of the mixture containing 6 % Bakelite, which showed increased strength. Although there is a slight reduction in flexural strength, Bakelite waste prevents sudden specimen breakage and maintains specimen integrity. The ultimate load capacity of reinforced concrete beams with Bakelite waste is generally lower compared to the control beam, except for the 8 % waste Bakelite beam which demonstrated a similar ultimate load capacity of 60 kN. Although managing Bakelite waste can be difficult because it can lead to the creation of microplastics in landfills over time, utilizing Bakelite waste in concrete can be a sustainable method of waste management. The innovative use of Bakelite waste as a partial replacement for coarse aggregate in concrete offers a sustainable solution to the problem of waste management and addresses the environmental concerns related to the disposal of non-biodegradable plastics. This research provides a practical solution for developing eco-friendly and cost-effective construction materials while promoting sustainable waste management practices

Effect of Design Parameters on the Flexural Strength of Reinforced Concrete Sandwich Beams

Sandwich beams are preferable for aerostructure and marine structures due to their high mechanical strength, durability, stiffness, and fatigue resistance. This paper presents a study on the flexural behavior of sandwich beams made of self-compacting concrete comprising a polystyrene inner core with wire mesh reinforcement. The effect of the design parameters such as the inner core area, percentage of tension reinforcement, and wire mesh on the moment carrying capacity and failure modes of sandwich beams was analyzed. Ten beams were cast and tested to failure with simply supported end conditions and they were classified into three different groups. The longitudinal section of the inner core area was varied by 0% (control beam), 25%, 50%, and 75% of the gross area. The tension reinforcement ratio varied between 0.6 and 1.5%. In addition, the effect of the wire mesh in shear and flexural resistance was studied. The load-carrying capacity of sandwich beams increased with flexural reinforcement. In addition, the welded wire mesh improved the sandwich beams’ flexural and shear performance. The conventional expressions for the moment of resistance were valid for sandwich beams, whereas the shear strength expressions overestimated the capacity; therefore, modifications were suggested. The refined models had a significant agreement with the experimental results

Destructive and non-destructive testing of the performance of copper slag fiber-reinforced concrete

Concrete technology is adopted worldwide in construction due to its effectiveness, performance, and price benefits. Subsequently, it needs to be an eco-friendly, sustainable, and energy-efficient material. This is achieved by replacing or adding energy-efficient concrete materials from industries, such as ground granulated blast furnace slag, steel slag, fly ash, bottom ash, rice husk ash, etc. Likewise, copper slag is a waste material produced as molten slag from the copper industry, which can be used in concrete production. Copper slag can perform roles similar to pozzolans in the hydration process. This paper extends the comparative study of copper slag concrete with polypropylene fiber (PPF) subjected to destructive and non-destructive testing. Under destructive testing, compressive strength of concrete cubes, compressive strength of mortar cubes, splitting tensile tests on cylindrical specimens, and flexural tests on plain cement concrete were conducted and analysed. Ultrasonic pulse velocity and rebound hammer tests were performed on the samples as per IS13311-Part 1-1992 for non-destructive testing. The 100% replacement of copper slag exhibited a very high workability of 105 mm, while the addition of 0.8% PPF decreased the flowability of the concrete. Hence, the workability of concrete decreases as the fiber content increases. The density of the concrete was found to be increased in the range of 5% to 10%. Furthermore, it was found that, for all volume fractions of fiber, there was no reduction in compressive strength of up to 80% of copper slag concrete compared to control concrete. The 40% copper slag concrete was the best mix proportion for increasing compressive strength. However, for cement mortar applications, 80% copper slag is recommended. The findings of non-destructive testing show that, except for 100% copper slag, all mixes were of good quality compared to other mixes. Linear relationships were developed to predict compressive strength from UPV and rebound hammer test values. This relationship shows better prediction among dependent and independent values. It is concluded that copper slag has a pozzolanic composition, and is compatible with PPF, resulting in good mechanical characteristics