UTILIZATION OF WASTE GLASS IN COMPOSITE CEMENT FORMULATIONS

• Main Author: JULYANA MANULLANG (NIM : NIM : 23015019), RIA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23940
• Institution: Institut Teknologi Bandung

The contribution of CO2 emissions from the Portland cement industry is the biggest compared to other industries emission to increasing Indonesia national CO2 emission. One of the ways to reduce CO2 emissions in the cement industry by partially substituting clinker in Portland cement products. Clinker can be substituted by inorganic materials as cement additives (supplementary cementitious materials or SCM). One such material is waste glass. Waste glass can improve properties of cement by pozzolanic reaction that occurs between the waste glass and cement. The utilization of waste glass in composite cement production has not been applied on a commercial scale, while the potential availability of waste glass in Indonesia is quite abundant. Most published studies on waste glass concern the pozzolanic characteristics of waste glass as aggregate material. Research on waste glass as SCM directly added with clinker is rarely do. This research purpose are to explore the feasibility of using waste glass as a clinker substitution and identify the formula variables that influence the physical properties and microstructure of composite cement. An extreme vertices mixture experimental design was selected, in which the relative proportions of clinker, waste glass and gypsum is chosen as the experimental variable. The effect of composite cement formulation on the hydrated product physical properties were evaluated statistically using the ANOVA method. Based on ANOVA results, the influence of composite cement formulation on the setting time can be modeled using linear model, while the effect of the component in composite cement on the compressive strength is modeled using linear and quadratic models. Increasing of glass amount at 15-25% could increase 30 – 110% of initial setting time. Increasing of gypsum and glass could improves the early strength of cement due to the lower amount of glass and secondary ettringite that forrmed in hydration of cement. The composite cements with glass amounts below 20% have a compressive strength that still meets requirement of SNI 15-7064-2004. The size of larger secondary etringitte crystals on composite cement causes the decreasing of compressive strength of cement. The content of remaining Ca (OH)2 in composite cement is not much different than OPC cement due to the less of pozzolan reaction betweeen glass and hydration product Ca(OH)2. The composite cement produces fewer hydration products formed than OPC cement.