Assessment of utilization of ceramic waste as a substitute to concrete constituents – A review Evaluación de la utilización de desechos cerámicos como sustituto de los componentes del hormigón – Una revisión

Due to high consumption of concrete constituents namely, natural aggregates and cement, their depletion is observed globally. Over the years, many researchers have come up with alternatives to these basic constituents of concrete. Ceramic waste (CW) generated from ceramic industries (industries producing tiles, sanitaryware, ceramic refractories, ceramic insulators, ceramic crockery) have not found any reuse and is deposited as landfills, which further increases land pollution and also give rise to health issues. The CW can be easily grinded as per required size, which have interested many researchers to use it in the production of concrete. Till date CW has been used as partial replacement to cement, fine aggregates and coarse aggregates. This review paper discusses the potential of CW as replacement to concrete constituents in the production of concrete and its effect on mechanical and durability properties. The literature review is carried in three parts – review on use of CW to replace cement, fine aggregates and coarse aggregate. The study shows different researches using different sources of CW having varied properties being used as partial replacement. The effect of replacement on concrete strength and durability is reported. en la producción de hormigón como reemplazo de los componentes y su efecto sobre las propiedades mecánicas y de durabilidad. La revisión de la literatura se llevó a cabo en tres aspectos: revisión sobre el uso de desechos cerámicos para reemplazar parte del cemento, agregados finos y agregados gruesos. El estudio muestra diferentes investigaciones que utilizan diferentes fuentes de desechos cerámicos, con propiedades variadas, utilizados como reemplazo parcial de alguno de los componentes. El estudio informa el efecto de este reemplazo parcial sobre la resistencia y durabilidad del hormigón. mecánicas better mechanical properties indicated higher pozzolanic reactivity. The results had larger differences at early age as compared to smaller differences at later curing age. Vacuum water absorption, capillary water absorption, Oxygen permeability, water permeability, Chloride diffusion test and accelerated aging test performed to study the durability properties of the mixes. All mixes with CWs performed better than control mix. experimentally observed basic and hygric properties of concrete mixtures with partial substitution of cement by fine ceramic powder (FCP). The reduction in water absorption was observed for the mixes with FCP replacement up to 10% of cement and for these mixes compressive strength at 28 days was slightly higher compared to control mix with no FCP. The mixes with higher content of FCP showed reduction in strength due to lower bulk density than control mix. (Kannan et al., 2017) evaluated high performance concrete (HPC) by replacing cement with CW and observed lower compressive strength at early age while comparable compressive strength at later ages for mixes containing CW. These mixes showed better durability performance. Microstructural investigations confirmed no significant difference in the hydration components in mixtures incorporating cement waste and the reference concrete mixture. The pozzolanic activity of CW was studied by Frattini test and suggested noticeable reactivity viz. due to filler effect and pozzolanic effect.


Introduction
Development of infrastructure have led to high demand of natural resources and as a result high depletion of these resources is observed. Also, industrial development has seen large amount of industrial waste which again is hard to dispose safely without affecting environment. This appears to be a challenging problem to the engineers but with pragmatic approach and implementing new techniques it may be converted into a problem with a solution: using industrial waste to meet the requirement of raw materials for the construction industry. This way, the wastes can be safely used to satisfy the ever-increasing demand of construction materials which will led to a cleaner and green environment. In addition, the replacement of concrete constituents with wastes can be helpful in producing economical concrete which may lower the over-all cost of a project.
Many research have been done to produce concrete with wastes like slag, fly ash, sugarcane husk, rice husk, rubber wastes, organic waste (Izquierdo et al., 2018), ceramic waste, electronic waste (Dhanabal et al., 2021) etc. by substituting concrete constituent with these wastes, either discretely or in combination. In recent years a lot of research has been done to produce concrete using ceramic wastes as replacement to cement and aggregates. While a comparative study of ceramic utilization as cement replacement and aggregate replacement is done by few authors (Pacheco-torgal and Jalali, 2010); (Bignozzi and Saccani, 2012), it is necessary to review previous study to identify the best use of ceramic waste to replace concrete constituents. This paper reviews work done by various researchers to investigate the potential of ceramic waste by replacing concrete constituents with it. This discussion is divided into three sections -work done by partial replacement of cement, work done by partial replacement of fine aggregates and work done by partial replacement of coarse aggregates. The properties of the CW are also reported. The development of strength and durability are also reported.

Replacement to Cement
The crushing of CW when crushed to fine powder can be helpful in achieving dense microstructure due to filler effect and the pozzolanic nature of CW can later play a role in imparting strength. This was evident by the works of (Kannan et al., 2017) and (Ding et al., 2020). (Ding et al., 2020)  The study on use of CW with different particle size (< 45 µm, 45-90µm and >90µm) to produce cement clinker revealed that the particles less than 90µm had better reactivity and higher burnability compared to traditional cement clinker (Puertas et al., 2008). The particle size of CW used to replace cement are coarser than the cement particles as confirmed from the studies of scanning electron microscope images by (AlArab et al., 2020), ( Li et al., 2019) and (Mohit and Sharifi, 2019); as shown in (Figure 1). This coarse nature of CW particles may tend to reduce filler effect and pozzolanic reactivity (AlArab et al., 2020)). Moreover, CW particles consist of irregular and angular particles similar to cement particles (Kannan et al., 2017). The specific surface area (SSA) of CW powders reported by various authors is compiled in (Table 1) and in most of the studies, SSA of CW is higher compared to SSA of cement. Thus, higher surface area is also an indication of higher reactivity. The fineness of powder may affect the mechanical and durability properties (Betancourt and Martirena, 2011). The clinker and cement containing CW as an alternative raw material had similar characterization as of regular cement (Puertas et al., 2010). (Figure 2) shows ternary diagram of commonly used supplementary cementitious material recreated from (Bignozzi and Saccani, 2012).   The mix with CB waste had better mechanical properties which indicated higher pozzolanic reactivity. The results had larger differences at early age as compared to smaller differences at later curing age. Vacuum water absorption, capillary water absorption, Oxygen permeability, water permeability, Chloride diffusion test and accelerated aging test were performed to study the durability properties of the mixes. All mixes with CWs performed better than control mix. (Heidari and Tavakoli, 2013) confirmed pozzolanic activity of ceramic powder obtained by grounding recycled ceramic ground tiles and studied mechanical properties of concrete. It was observed that with higher proportion of CW, the compressive strength reduced. Also, at later stages, minor strength loss was observed indicating good pozzolanic reactivity. The use of CW also helped in reducing water absorption capacity, as every concrete mix with CW showed better performance as compared to control mix. (Reiterman et al., 2014) experimentally observed basic and hygric properties of concrete mixtures with partial substitution of cement by fine ceramic powder (FCP). The reduction in water absorption was observed for the mixes with FCP replacement up to 10% of cement and for these mixes compressive strength at 28 days was slightly higher compared to control mix with no FCP. The mixes with higher content of FCP showed reduction in strength due to lower bulk density than control mix. (Kannan et al., 2017) (Torres-Carrasco and Puertas, 2017). For all the above reported values in (Table 1),

SiO2 +Al2O3 +Fe2O3 > 70% SO3 < 3% LOI < 10%
This indicates pozzolanic reactivity as per ASTM C618-08a.   Figure 3) shows variation in 28-day compressive strength of the mixes prepared with partial replacement of cement with CW, relatively with a control mix with no CW. The strength of control concrete mix is compared with strength of concrete mix with ceramic waste having highest strength (maximum) and the lowest strength (minimum). The compressive strength at 28 days is at par with the control mix and the loss in strength is very negligible. From above literature review it can be said that the replacement of cement by CW results into lower or similar strength at early age and later the strength increases. This is because replacement of cement lowers the strength at early stage but at later stages due to the pozzolanic activity of CW with hydrated cement products, the strength increases. (López et al., 2007) investigated physical and mechanical properties of concrete mix by replacing conventional sand with white ceramic powder. The compression, flexural strength and Brazilian (tensile splitting strength) test showed that the concrete mix with CW had better compressive strength and same mechanical characteristics as that of control mix with conventional sand. (Torkittikul and Chaipanich, 2010) assessed the effect of CW on fresh and hardened properties of concrete by replacing natural sand with CW. It was observed that for concrete with CW, density was lower than control mix without CW. These concrete mixes also showed higher compressive strength compared to control mix.  (Pacheco-torgal and Jalali, 2010) examined ceramic-based concrete by replacing natural sand with ceramic sand to determine strength and durability properties. The concrete mix with CW showed higher strength than control mix. The CW based concrete showed better results in capillary water absorption; almost 50% less compared to control concrete mix. The CW based concrete performed better than control mix in oxygen permeability test and chloride diffusion test. (Siddique et al., 2017) examined fresh and hard properties of the concrete produced by replacing natural sand with bone-china aggregate as fine aggregate. It was observed that with increase in the content of CW, fresh density increased & air content decreased however, compressive strength and bleeding increased.

Replacement to Fine Aggregate
The basic properties of CW used as fine aggregate as reported by various authors is compiled in (Table 2). The specific gravity is in the range of 2-2.5 which is very similar to natural fine aggregates. (Figure 4 shows variation in 28day compressive strength of the mixes prepared with partial re-placement of fine aggregates with CW, relatively with a control mix with no CW. The literature review suggests that the replacement of traditional fine aggregates with CW aggregate does not compromise with the compressive strength and also performs better from durability aspects. The increase in strength can be attributed to the fact that fines from CW fills the voids and helps in achieving dense matrix which over-all increases compressive strength.

Replacement to Coarse Aggregate
The CW obtained from the field has to be crushed to get coarse aggregate-sized particles. The basic properties of the crushed ceramic coarse aggregate reported by various authors is compiled in (Table 3).
The fresh and hardened properties of the concrete prepared by replacing crushed stone aggregate (obtained from ceramic electrical insulator industrial waste) was studied by (Senthamarai and Devadas, 2005) with CW aggregate and observed more workability than conventional concrete due to smooth surface of CW aggregate. Overall, it was observed that the properties of CW aggregate concrete were similar to conventional concrete. The concrete with CW showed better permeation characteristics and with the decrease in water/cement ratio performance decreases (Senthamarai et al., 2011). (Pacheco-torgal and Jalali, 2010) examined ceramic-based concrete by replacing coarse granite aggregate with ceramic coarse aggregate to determine strength and durability properties. The concrete mix with CW showed higher strength than control mix but underperformed in durability properties. (Medina et al., 2012a) partially substituted natural coarse aggregate with recycled ceramic aggregate (obtained from sanitaryware manufacturer) to study physical and mechanical properties of structural concrete. The mineralogical composition showed that interfacial transition zone (ITZ) between paste and recycled ceramic aggregate was more compact, narrower and less porous than that between paste-gravel. It was observed that concrete with CW showed higher performance in compressive and tensile strength tests. (Rashid et al., 2017) partially replaced conventional coarse aggregate by CW aggregate to experimentally assess fresh and hardened properties of the concrete thus produced. It was observed that workability decreased and compressive strength increased with increase in proportion of CW (attributed to glassy surface and rough shape of CW aggregate). Also, by using analytical hierarchy process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS), concrete made with 30% replacement was selected as best sustainable recycled concrete.

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(Ogawa et al., 2020) investigated use of porous CW as internal curing agent in steam-cured concrete using fly ash by replacing natural coarse aggregate in the replacement ratio of 0%, 10%, and 20% by volume. This porous CW coarse aggregate significantly improved compressive strength and carbonation resistance of concrete. (Yasin Mousavi et al., 2020)

Conclusions
This literature review on ceramic waste (CW) has identified it as a potential replacement to concrete constituents. Following conclusions are drawn from this study: The major chemical composition of the CW includes Silica (>60%) and Alumina (> 15%) with (SiO2 +Al2O3 +Fe2O3) content more than 70%. (ii) The specific surface area of the CW powder is higher than the cement which implies higher reactivity. (iii) CW has been successfully used to replace cement content partially without significantly loss in compressive strength. However, as reported, CW obtained from different sources may have variation in material properties. Thus, it becomes highly essential to characterize the CW. (iv) The basic material properties like specific gravity, water absorption and fineness modulus are nearly similar to that of natural fine aggregates. (v) The replacement of fine aggregates with CW, as reported, in many cases have improved the over-all performance of the concrete. This is due to the fact that CW as fines helps improving workability and later due to their pozzolanic nature imparts strength to the mix. (vi) The replacement of coarse aggregate with CW has observed lower workability due to the rough and angular surface of CW aggregate, however, compressive strength was improved.
The use of CW as substitution to fine aggregates is more preferable as it aids in achieving better workability, compressive strength and durability than conventional aggregates.