**Abstract**

The global production of ceramic waste powder (CWP), which is produced during the final polishing process of ceramic tiles, exceeds 22 billion tons. The disposal of CWP in landfills will cause significant environmental problems (i.e., soil, air, and groundwater pollution). CWP is characterized by its chemical composition that is mainly composed of silica (SiO2) and alumina (Al2O3). Both minerals represent more than 80% of the CWP composition. CWP has potentials to be used as an ingredient to partially or entirely replacing Portland cement to make eco-friendly concretes. This chapter summarizes the effect of using CWP in making eco-friendly concretes, with a particular focus on using CWP as a partial cement replacement in conventional-vibrated concrete (CVC) and self-compacting concrete (SCC), and the production of zero-cement alkali-activated concrete (AAC).

**Keywords:** ceramic waste powder, cement replacement, eco-friendly concrete, durability, microstructure

## **1. Introduction**

In a rapidly growing world population and toward meeting consumers' needs, solid waste landfills will continue receiving huge volumes of waste. Therefore, waste management is becoming increasingly mandatory for the promotion of environmental sustainability. Numerous regulations have been imposed worldwide by governments and environmental organizations in order to reduce the negative environmental impact resulting from large numbers of solid waste landfills. The transformation of a large amount of solid waste into an alternative resource will preserve the reducing nonrenewable resources of materials; maintain the required energy and also will help solve environmental and exhausted landfill problems. Until today, researchers are investigating new solid waste materials and the potentials of recycling either in other industries or new products.

Being the world's most consumed human-made material, concrete attracted considerable interest as a possible way to recycle solid waste products especially those that can replace cement which is a significant contributor to global greenhouse gas emissions. An equal amount of CO2 is generated for the production of Portland cement [1]. The cement industry produces around 5–8% of the annual global greenhouse gas emissions released into the atmosphere [2]. Several by-products such as

fly ash, slag, and silica fume are effectively being used in the daily production of concrete as partial cement replacement (i.e., supplementary cementitious materials (SCM)) to reduce CO2 emission [3, 4].

Global production of ceramic tiles is more than 12 Billion m2 [5]. The manufacture of ceramic tiles generates ceramic waste powder (CWP) during the final polishing process at a rate of 19 kg/m<sup>2</sup> [6]. Therefore, the global generation of CWP exceeds 22 Billion tons. The CWP represents a significant challenge to get rid of concerning its environmental impact. It can cause, soil, water, and air pollution. On the other hand, it could represent an excellent opportunity to be used as an alternative concrete ingredient if it could be utilized in making concrete.

The effect of using ceramic wastes (i.e., roof tiles, blocks, bricks, electrical insulators, etc.) as aggregates or SCM in conventional-vibrated concrete (CVC) and mortar was reported in several studies. It is noted that limited studies were conducted on using CWP as a cement replacement in self-compacting concrete (SCC) and alkali-activated concrete (AAC) (i.e., geopolymer concrete). Some studies investigated the use of ceramic waste as coarse aggregates in CVC and mortar [7–16]. It was concluded that ceramic waste could be used as partial replacement of natural coarse aggregate. The ceramic waste aggregate should be pre-saturated by water to offset its high absorption. The compressive strength decreased if the ceramic waste replaced natural coarse aggregate beyond 25% by weight. The use of ceramic waste as fine aggregate in CVC and mortar was assessed by various researchers [16–22]. It was noted that using a high content of ceramic waste as fine aggregate had a negative impact on the workability of the fresh concrete, and workability admixtures were needed to avoid any adverse effect on concrete workability. It was concluded that the use of 50% by weight replacement of fine natural aggregate by ceramic waste could produce concrete without affecting the performance of hardened concrete.

The use of CWP as partial replacement of cement attracted the attention of several researchers [6, 23–35]. The main conclusion from the studies was that CWP showed slow pozzolanic activity which was evidenced at late ages. The early compressive strength was reduced by the inclusion of CWP. The development of compressive strength needed time. On the other hand, durability was improved by the incorporation of CWP in the mixtures. It was noticed that the investigations on using CWP as partial replacement of cement did not address the fresh concrete properties as affected by the inclusion of CWP as well as the microstructure characteristics. Also, no guidelines were provided for using CWP to partially replace cement. The CWP replacement level will depend on personal knowledge and experience. Furthermore, the replacement of cement by large quantities of CWP needs further evaluation.

The use of CWP in self-compacting concrete (SCC) mixtures received limited attention. In 2017, Subaşi et al. [36] investigated the use of CWP as a partial cement replacement in SCC mixtures. It was concluded that CWP could replace 15% by weight of the cement without adversely affecting the properties of the produced SCC. In 2018, Jerônimo et al. [37] replaced cement by ground clay brick waste (GCBW) in SCC mixtures. It was concluded that 20–30% by weight of the cement could be replaced by GCBW, and the compressive strength improved at 90 days of age. It was observed that the detailed evaluation of the SCC fresh properties as affected by the inclusion of CWP was not addressed. Also, the effect of using highvolume CWP in SCC still needs further assessment.

Concerning using CWP in alkali-activated concrete (AAC) (i.e., geopolymer concrete), it was noted that very limited investigations were conducted [38–40]. The main conclusion that CWP could be used in making AAC but needs detailed investigation and assessment.

**9**

**Figure 1.**

*The Use of Ceramic Waste Powder (CWP) in Making Eco-Friendly Concretes*

cement and efficiently getting rid of a solid waste material.

An in-depth investigation to study the utilization of CWP in the production of different types of concrete is needed. This chapter summarizes the findings of collective studies conducted by the authors investigating the use of CWP in making eco-friendly concrete [41–45], with a particular focus on using CWP as a partial cement replacement in CVC and SCC, and the production of AAC. This will establish better understanding on how to incorporate an existing solid waste as a new construction ingredient in making echo-friendly concretes in order to optimize solid waste management, and help protect the environment by reducing the use of

The produced ceramic waste material was a wet material due to the use of water during the polishing process. The average moisture content was 36% by mass. The average specific surface area (SSA) measured by air-permeability (i.e., Blain air

particles had a size ranging between 5 and 10 μm. **Figure 1** shows the particles' size

The CWP consisted of irregular and angular particles which are similar to cement particles in shape as shown in the scanning electron microscope (SEM) image in **Figure 2**. **Figure 3** shows the energy dispersive spectroscopy (EDS) of the main oxides of the CWP. The EDS analysis indicated that CWP is mainly composed

**Table 1** gives the chemical analysis of the CWP as determined by X-ray fluorescence (XRF). CWP is mainly composed of silica (SiO2) and alumina (Al2O3). Both oxides are around 85% of the total material mass. Other compounds (i.e., CaO, MgO, and SO3) exist in small quantities. The mass fractions of (SiO2 + Al2O3 + Fe2O3) satisfies the requirement of the ASTM C618 [46] for natural pozzolana (i.e., >70%). Also, the SO3 and the loss on ignition (L.O.I.) conformed to

*Particle size distribution of CWP [43]. Reproduced with permission from the publisher.*

/kg. More than 50% by volume of the CWP

*DOI: http://dx.doi.org/10.5772/intechopen.81842*

**2. Characteristics of CWP**

distribution of the CWP.

the ASTM C618 requirements.

of SiO2 and Al2O3.

permeability test apparatus) was 555 m2

*The Use of Ceramic Waste Powder (CWP) in Making Eco-Friendly Concretes DOI: http://dx.doi.org/10.5772/intechopen.81842*

An in-depth investigation to study the utilization of CWP in the production of different types of concrete is needed. This chapter summarizes the findings of collective studies conducted by the authors investigating the use of CWP in making eco-friendly concrete [41–45], with a particular focus on using CWP as a partial cement replacement in CVC and SCC, and the production of AAC. This will establish better understanding on how to incorporate an existing solid waste as a new construction ingredient in making echo-friendly concretes in order to optimize solid waste management, and help protect the environment by reducing the use of cement and efficiently getting rid of a solid waste material.
