**8. Polymeric waste additives**

Polymers have been increasingly used over the last 50 years in almost every industry as well as in human daily life. However, these products are hazardous to the environment and almost impossible to recycle. Therefore, finding a useful way to reuse these products is a focus of research. One potential way to reuse polymers is to add them to concrete or mortar.

*Characterizations of Cement and Modern Sustainable Concrete Incorporating Different Waste… DOI: http://dx.doi.org/10.5772/intechopen.100447*

Daud et al. utilized thermoplastic polyethylene terephthalate (PET) waste obtained from recycling bottles to replace the graves in lightweight concrete used for insulation walls in building construction faces [38].

Plastic pollution is exacerbated by the constant manufacture and disposal of plastic. Jain et al. successively employed non-metallic polymeric plastic waste with flay ash in concrete and concluded that the addition of non-metalized waste plastic bag fibers together with fly ash in concrete greatly improved properties like split tensile strength, resistance to abrasion, flexural strength, impact, and drying shrinkage [39].

Another type of sustainable concrete incorporates waste rubber as an additive. Rubber is one of the hardest materials to recycle, thus the utilization and reuse of leftover waste rubber in concrete can minimize raw material consumption, resulting in economic efficiency and long-term development of the building sector. Yang et al. utilized waste tire rubber as a replacement for fine aggregates (sand) by reducing its size. The disposal of leftover waste tires has become a major environmental concern worldwide [40].

Concrete containing waste polymeric material can be utilized to reduce the contamination of radioactive material in the environment. Saleh et al. incorporated recycled PET waste with cement into making container-like material for reducing the activity of radioactive borate waste obtained from pressurized water reactor (PWR). They provided a characterization for these samples and concluded that the combination of cement with PET is an acceptable product for immobilization of radioactive borate [41].
