Ceramic Coarse Aggregate Research Articles

Influence of Ceramic Wastes as a Recycled Coarse Aggregate with Different Maximum Sizes on the Concrete

Background Natural raw resources needed for concrete construction are continuously being depleted as a result of infrastructure development that is increasing. As a result, waste material substitutes are highly favored because they adopt a sustainable strategy. Objective In this study, the possibility of substituting natural coarse aggregates with coarse aggregate made from ceramic wall tiles with three different maximum aggregate sizes (12.5, 19, and 25 mm) in three partial replacement levels of natural coarse aggregate by (25, 50, and 75%) was investigated. Methods Concrete's hardened density, compressive and splitting tensile strengths, ultrasonic pulse velocity, water absorption, and volume of permeable pores were all tested experimentally. Results Results indicated that with the increment of the maximum aggregate size, each of the hardened densities, the compressive and splitting tensile strengths and the rate of water absorption diminished while pulse velocity enhanced, regardless of the substitution rate of ceramic aggregate. However, for all maximum aggregate sizes, the mixture containing 25% ceramic coarse aggregate showed a small improvement in mechanical properties. Compared to the reference mixture, which had compressive strengths of 29.31, 38.73, and 47.13 MPa at 7, 28, and 90 days for the 12.5 mm maximum aggregate size, the improvement ratios were 8.9%, 3.7%, and 2.7% at 7, 28, and 90 days, respectively. Moreover, because of increased heterogeneity, internal bleeding, and the development of microcracks in the larger coarse aggregate sizes, concrete with lower ceramic coarse aggregate sizes has a stronger bond than that of the latter. Results also indicated that the mechanical performance of concrete mixtures having ceramic aggregate slightly improved with 25% ceramic coarse aggregate, then lowered in the mixtures with 50% and 75%, consecutively, at all ages. Concrete using ceramic aggregate displays a poor transition zone because of the improper binding between the paste and the coarse ceramic aggregate caused by the aggregate's porcelain texture. Additionally, the water absorption of concrete mixtures containing ceramic aggregate increased with the increase in the percentage of ceramic coarse aggregate. Conclusion The employing of ceramic waste aggregate was shown to contribute to sustainable development and a cleaner environment by producing sustainable concrete from the recycling of ceramic wastes. Each of the hardened density, compressive strength, splitting tensile strength, and water absorption of concrete mixtures decreased and the pulse velocity enhanced as the maximum aggregate size increased. The mechanical properties decreased at all ages in the mixtures containing 50 and 75% of the aggregate, whereas they slightly increased in the mixture containing 25% of the aggregate.

Structural retrofitting of RC slabs using bamboo fibre laminate: Flexural performance and crack patterns

Enhancing the durability of structural elements is a viable approach to promote sustainability in civil engineering. Research has shown that well-maintained slabs outperform degraded ones, which deteriorate rapidly due to insufficient upkeep. The occurrence of cracking and deformation in slabs subjected to sustained loads significantly impacts their functionality. However, the implementation of appropriate retrofitting techniques utilizing locally available materials can effectively minimize deflection and crack propagation while also improving flexural capacity. This particular study aimed to evaluate the flexural performance of slabs that were retrofitted using bamboo fibre laminate (BFL). Also, the study investigated two alternative replacement methods alongside the conventional mix; one involved replacing all fine aggregates with ceramic fine aggregate and the other involved a complete replacement of coarse aggregates with ceramic coarse aggregate. These mixes were represented in both the retrofitted and non-retrofitted samples. The retrofitting process included using the combined external bonding and near surface-mounted method. Twelve slab samples were made, with six being non-retrofitted and the other six retrofitted with BFL. Each of the samples had dimensions of 300 mm × 300 mm × 50 mm for reinforced concrete (RC) slabs. The slabs were tested employing the three point-bending system, and the retrofitted slabs with the conventional mix exhibited the highest ultimate failure load and flexural strength (62.1 kN), which compared to the non-retrofitted slabs of the same mix was a 60.76% increase. Additionally, the study did a thorough analysis of the presence of flexural and diagonal shear cracks, as well as the occurrence of debonding between BFL and the slabs. Non-destructive tests were also conducted on the slab samples to further confirm accurate results. These findings offer helpful insights into the development and application of a sustainable retrofitting material that can remarkably improve RC slabs.

Axial compressive behavior of recycled ceramic coarse aggregate concrete-filled steel tubular columns

A series of axial compressive tests were performed on recycled ceramic coarse aggregate concrete (RCCAC) cubes and prisms, as well as 36 recycled ceramic coarse aggregate concrete-filled steel tubular stub columns (RCCAC-FSTs) in the present study. RCCAC failure mechanisms, compressive strength, elastic modulus, and microstructure were studied. In addition to the cross-sectional type, the steel content, the confinement factor, and the replacement ratio of recycled ceramic coarse aggregate (RCCA) were chosen as primary variables to investigate the passive confinement effect of RCCAC-FSTs. Analysis of the typical failure modes, the Load (Nue)-longitudinal strain (εL) curve, the Load (N/Nue)-hoop strain (εh) curve, the ultimate bearing capacity, the ductility, and the effect of RCCA replacement ratio were successively performed. The results suggest that the confinement factor determines the development pattern of the load–strain curves, while the use of RCCA influences the failure mode, the elastic modulus, the ultimate strength, the critical strain, and the ductility of specimens. The critical confinement factor for circular and square specimens was also determined. A stress–strain model of RCCAC restrained by steel tube was established and verified through finite element analysis based on a database of test results presented in the present study and existing research.

Finite element analysis and bearing capacity of CRACFDSST columns under eccentric compression

The mechanical behaviour of ceramic recycled aggregate concrete-filled double-skin square steel tubular (CRACFDSST) columns under eccentric compression, with changing slenderness ratio, eccentricity and hollow section ratio parameters, was investigated, and 12 columns were tested. The test results indicated that all specimens exhibited elastic–plastic instability failure. No cement-based materials attached to the ceramic glaze surface were observed at the crushed position. Additionally, the CRACFDSST columns had good ductility and bearing capacity. The constitutive relationship of ceramic recycled concrete constrained by the square steel tube was adopted to establish finite element (FE) models, which considered the plastic damage of concrete. The FE calculation results agreed well with the experimental results. FE analyses of ceramic recycled concrete and ordinary concrete members were conducted, and the stress distributions of the steel tubes and concrete, the load–deflection curves at the mid-span, and the interaction between the steel tubes and concrete of the members were compared. Subsequently, 312 FE examples were used to analyse the effects of the steel yield strength, concrete strength, hollow section ratio, nominal steel ratio, diameter-to-thickness ratio of the inner steel tube, slenderness ratio and ceramic coarse aggregate replacement rate on the moment-load curves. Ultimately, a simplified formula was proposed to predict the bearing capacity of CRACFDSST columns under eccentric compression.

Design of a non‐shrinking silica fume high‐performance concrete with recycled ceramic tile aggregate

AbstractInternal curing (IC) process introduced via a water‐entraining agent using lightweight and porous aggregate has become an essential component in designing high and ultra‐high‐performance concrete (HPC/UHPC). This paper presents experimental results demonstrating the effectiveness of using recycled ceramic tile aggregates (RCTA) derived from waste ceramic tiles as an IC agent for high‐performance structural elements. Previous studies by the author have confirmed the efficiency of both the pre‐saturated recycled porous ceramic coarse aggregate (RPCA) as an IC and shrinkage compensating agents in mitigating autogenous shrinkage and the induced internal self‐stress in HPC mixtures. The main objective of this study is to investigate the effect of two different curing systems (internal curing using the waste ceramic aggregate combined with shrinkage compensating agents) on silica fume (SF) HPC behavior. The shrinkage compensating agents include a combination of shrinkage‐reducing agent (R) and expansive additive (E). The influence of this combined ternary curing system on the mechanical properties, including compressive, flexural, and splitting tensile strengths, modulus of elasticity, autogenous shrinkage, and internal self‐induced tensile stress, were investigated. The obtained results indicate a substantial reduction in the autogenous shrinkage strains magnitude and, consequently, the internal self‐induced tensile stress in the HPC mixtures designed with these two curing systems. It was also found that this combination of the two curing systems resulting in a hybrid curing system, performs much better than the single incorporation of shrinkage‐compensating agents. Besides, a long‐term strengths improvement was recorded for mixtures designed with the RPCA. Incorporating recycled aggregate in the design and production of HPC could further promote concrete sustainability by reducing the amount of virgin extracted non‐renewable minerals, reducing the energy required to extract and process natural aggregates and the CO2 generated, and also reducing solid waste materials disposal.

Characterization of PVA Fiber-Reinforced Pervious Concrete with Blended Recycled Ceramic Aggregates and Natural Aggregate

Effective industrial waste management is one of the important challenges facing modern society. Ceramic wastes occupy an important proportion of industrial waste. The utilization of waste of ceramics is becoming more and more attractive for many researchers to alleviate the environmental impact of industrial waste. As a low-impact development method, pervious concrete (PC) received more and more attention from researchers in recent years. However, the relatively low strength compared with ordinary concrete restricts the application of pervious concrete. This research used recycled ceramic coarse aggregates (RCCA) to partially replace natural coarse aggregates (NCA) to prepare recycled ceramic coarse aggregate pervious concrete (RCCAPC) and fiber-reinforced RCCAPC incorporating polyvinyl alcohol (PVA) fibers, and the effect of the replacement rate of RCCA and the amount of PVA fiber on the mechanical properties and permeability was investigated. The results show that RCCA can improve the mechanical properties of PC at a low substitution rate, as well as PVA fiber, and when the PVA content is about 0.3%, the enhancement effect is the best. Both RCCA replacement rate and PVA fiber content have little effect on the permeability coefficient of PC. Based on described studies, using RCCA to partially replace NCA at a low substitution rate is suitable for the preparation of PC, and PVA fibers can enhance the strength of PC, which may help to broaden the application scenarios of PC.

Bond between steel and concrete made with ceramic waste aggregate

Abstract The reduction of natural resources combined with a substantial increase in the generation of solid waste in large urban centers, justifies the search for methods of reusing the construction industry waste. The ceramic industry has a high disposal rate during the manufacturing, transportation and eventual replacement of its products. In this case, research on the reuse of ceramic materials is urgent. A possible solution is the employment of ceramic waste as a coarse aggregate in structural concrete. Therefore, the mechanical properties of this new mix of concrete have to be assessed. This study evaluates the bond strength between steel rebar and concrete with ceramic waste aggregates, by means of the pull-out test method, proposed by RILEM-FIP-CEB (1978). Three concrete mixtures were produced: a mixture without any replacement, and two other mixtures with gradual substitution of natural coarse aggregate by ceramic coarse aggregate (40% and 100% substitution, in volume). Nine cylindrical specimens, three for each of the concrete mixtures, were evaluated in laboratorial conditions. Results concerning bond stress between concrete and steel rebar indicated the feasibility of employing ceramic waste to replace part of the coarse aggregate in structural concrete.

Influence of Using Recycled Ceramic Aggregate and Ultra-fine Sand in Combination on Compressive Strength of Concrete

Recycled ceramic mixed sand (RCMS) was obtained through mixing recycled ceramic coarse sand (RCCS) and ultra-fine sand. Recycled ceramic mixed aggregate concrete (RCMC) was made by using RCMS as fine aggregate, partial substituting recycled ceramic coarse aggregate for crushed stone as coarse aggregate, respectively. Effect of the percentage of RCCS in RCMS was investigated. Experimental results indicate that the optimal percentage of RCCS in RCMS was between 50% and 60%, which could increase the compressive strength of RCMC by 8.19% to 8.44% than that of reference concrete. Moreover, an adjustment coefficient of RCMS which could reflect the effect of the percentage of RCCS on compressive strength of RCMC was proposed. By using regression analysis, the regression equation was obtained between a adjustment coefficient of RCMS and the percentage of RCCS, which could provide reference for choosing reasonable RCCS content and estimating the strength of RCMC. The consumption of recycled ceramic aggregate could reach 30.37% to 33.84% of total weight of aggregate in producing concrete, and this method of recycling waste ceramic is energy-saving and environment friendly.

Green concrete production with ceramic wastes and laterite

Laterite is a dominant soil material in Nigeria but its use in structural concrete has not been overly explored. In this study, ceramic wastes obtained from construction and demolition activities and laterite were used as replacement for natural aggregates. Workability and strength characteristics of the concrete and microstructure of selected samples were obtained. Results showed that natural aggregate concrete was more workable than the laterised concrete. Both the compressive strength and splitting tensile strength increased with curing age, however, laterised concrete with 10% laterite content and 75% ceramic coarse aggregate yielded higher strength at 28days than the reference concrete.

Preparation and Properties of High-Performance Concrete with Ceramic Coarse Aggregate

High-performance concrete was prepared by using ceramic waste as coarse aggregate. The influences of several factors, such as the contents of ceramic coarse aggregates, fly ashes and silica fumes, on the properties of concrete material were investigated. The results show that the compressive strength of semi-porcelain coarse aggregate concrete are slightly lower than that of natural concrete, and the splitting tensile strength and the ratio of compressive strength and splitting tensile strength is similar to the ones of natural concrete. After fly ash and silica fume mixed, the compressive strength, the splitting tensile strength and the resistance to water penetration of concrete with semi-porcelain coarse aggregate increase significantly with the increase of silica fume content which meet the requirements of high-performance concrete. Concrete with orcelain coarse aggregate is only suitable for low strength concrete.

The effect of high temperature on the residual mechanical performance of concrete made with recycled ceramic coarse aggregates

SummaryThis paper presents an experimental study on the residual mechanical properties of concrete with recycled ceramic coarse aggregate (RCCA) after exposure to elevated temperatures. Four concrete mixes were produced: a control concrete and three concrete mixes with replacement ratios of 20, 50 and 100% of natural aggregate (NA) by RCCA. The specimens were subjected to temperatures of 200, 400 and 600°C, for a period of 60 min. After cooling down to room temperature, the following concrete properties were evaluated: (i) compressive strength; (ii) splitting tensile strength; (iii) modulus of elasticity; (iv) ultrasonic pulse velocity (UPV); and (v) water absorption by immersion. At ambient temperature, as expected, the replacement of NA by RCCA resulted in a performance reduction of concrete. After exposure to elevated temperature, in general, the results obtained indicated an improvement of the residual relative mechanical properties of the mixes with RCCA, particularly after exposure to 400 and 600°C. However, exposure to the highest temperature (600°C) tended to cause spalling in concrete mixes containing RCCA. Significant linear correlations were observed between the residual compressive strength of all concrete mixes and both the UPV and the water absorption by immersion. Copyright © 2014 John Wiley & Sons, Ltd.

Microstructure and properties of recycled concretes using ceramic sanitary ware industry waste as coarse aggregate

Due to its physical, chemical and mechanical properties, the waste inevitably generated by the ceramic sanitary ware industry can be used in the production of concrete. This article reports the possibility of substituting 15%, 20% and 25% of natural coarse aggregate with recycled ceramic coarse aggregate, and presents an analysis of the resultant effects on the morphology and microstructure of recycled concretes, and consequently, on the mechanical behaviour of these ecoefficient concretes. The results demonstrate that ceramic waste does not interfere in either the hydration process or in the morphology of the hydrated products. The microstructure present in the interfacial transition zone (ITZ) of the recycled aggregate–paste is more compact and stable than that of the natural aggregate–paste. As regards mechanical behaviour, it was observed that as the percentage of substitution rose, the compressive strength of these concretes improved.

Effect of Curing Methods on Autogenous Shrinkage and Self-Induced Stress of High-Performance Concrete

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Desempenho de concretos com agregados reciclados de cerâmica vermelha

Os resíduos de construção e demolição (RCD) constituem uma importante parcela dos resíduos sólidos produzidos nas cidades brasileiras, correspondendo em torno de 50% dos resíduos sólidos urbanos. Dentre os diversos constituintes do RCD, a cerâmica vermelha, proveniente de restos de tijolos e telhas cerâmicas utilizados nas construções, equivale a uma considerável parcela destes resíduos. A reciclagem do RCD para a produção de agregados reciclados tem se tornado uma prática cada vez mais comum, particularmente em cidades onde há uma inacessibilidade ou escassez de agregados naturais, proporcionando altos custos para adquiri-los. Com o intuito de se determinar o comportamento do agregado reciclado de cerâmica vermelha na produção de concretos, desenvolveu-se um programa experimental baseado em um projeto de experimentos onde se substituiu os agregados miúdos e graúdos naturais pelos seus respectivos reciclados, além de se variar a relação água/cimento. Os concretos produzidos foram analisados com relação a três propriedades: resistência à compressão, módulo de deformação e volume de poros permeáveis (VPP). Os resultados obtidos foram analisados utilizando-se ferramentas estatísticas, desenvolvendo-se modelos matemáticos que descrevem o comportamento das propriedades estudadas ao se substituir o agregado natural pelos reciclados de cerâmica vermelha. Todos os modelos obtiveram excelentes coeficientes de determinação, acima de 95%. Simulações realizadas utilizando-se os modelos propostos apontam que a substituição do agregado miúdo natural pelo miúdo reciclado resulta em um acréscimo da resistência à compressão dos concretos produzidos e para a substituição do agregado graúdo natural pelo graúdo reciclado, um decréscimo. Para as demais propriedades do concreto estudadas, observou-se que a utilização dos agregados reciclados, tanto graúdo quanto miúdo, influi negativamente no comportamento do concreto, sendo que o agregado do tipo graúdo reciclado exerceu em todas as propriedades, uma maior influência.