# Feasibility of Non-Remanufactured Waste Bottle Glass as Supplementary Cementitious Material
## 1 Introduction
Glass is a versatile material and part of society's daily life in many fields and for different purposes, such as packaging or container and decoration (e.g., bottles, jars), flat glass (e.g., windows, windscreens), bulb glass (e.g., light globes), and cathode ray tube glass (e.g., TV screens, monitors) [16]. Glass products or elements often have a limited useful life and are discharged [17; 18; 19]. Theoretically, glass can be recycled entirely, but there are several requirements for remanufacturing. Thus, the glass fraction that cannot be introduced in the remanufacturing process is usually disposed of in landfills [16]. About 200 million tons of glass are estimated to be landfilled worldwide annually, with 80% of the glass disposal being soda-time glass, widely used in beverage bottles [16]. But glass is a non-biodegradable material; thus, waste glass can take one million years to break down naturally when landfilled [16]. Therefore, recycling waste glass has been a global concern to the scientific community [20]. Recycling glass waste in construction material, particularly crushed glass, has been under scrutiny over the last 70 years. Various applications can be found in a literature survey, such as using crushed waste glass as aggregate in subbase and unbound base mixtures, aggregate in asphalt mixtures, and SCMs and/or aggregate in cementitious materials. Ground waste glass mainly consists of silicon and calcium with an amorphous structure. Previous research shows that glass powder can be considered a pozzolanic-cementitious material according to the chemical requirements in ASTM C 618 and NP 4220; only the alkali content fails [21; 22]. The pozzolanic properties of ground waste glass, when very fine grounded, motivated several researchers to use it as a partial cement replacement [16; 20; 21; 22; 23; 24; 25]. Therefore, the main findings concerning recycling waste glass powder (finely milled waste glass, glass powder--GP) as a cement replacement for concrete applications in terms of mechanical and durability performance are described below. More detailed information is available in exhaustive review articles [15; 17; 20]. Incorporating glass powder (GP) generally improves the workability of fresh mortar or concrete [21; 22; 23; 26; 27; 28]. Other studies argue that waste glass influences cement replacement on slump and other engineering properties depending on the glass powder type and properties [29; 30]. [PERSON] et al. [31] studied the compressive strength development of mortars with glass powder as a cement replacement for up to 90 days, varying glass powder fineness and incorporation dosage. The results revealed that increasing GP dosage from 10% to 40% reduced compressive strength gradually. However, the pozzolanic reactivity of GP was observed after 28 days since the pozzolanic reaction is enhanced with particle size reduction, resulting in significant strength increments at later ages. According to the literature, compressive strength generally decreases slightly with the increase in GP dosage, and the optimum content seems to be between 10-30% of GP used as a cement replacement. However, the finer the glass used, the higher the concrete strength, especially at a late age (90 days) [15; 20; 21; 23; 24; 25; 32]. In fact, past research evidence that glass powder pozzolanic reactivity depends on particle size. Generally, glass powder particles below 75 \(\upmu\)m were very reactive, especially below 38 \(\upmu\)m [16; 33; 34; 35; 36; 37; 38; 39]. The pozzolanic reactivity of GP is governed by the particle size [21]. Glass powder particle size is also a key factor regarding deleterious alkali-silica reaction (ASR) expansion. The body of literature states that particles below 300 microns do not contribute to the reaction [17; 40; 41]. In fact, micro-sized glass particles can even mitigate expansion due to the ASR [22; 25; 42].