Characterization of Ceramic‐Based Construction and Demolition Waste: Use as Pozzolan in Cements

Abstract

Depending on its composition and properties, construction and demolition waste (C&DW) may be used today as recycled aggregate to manufacture more eco‐efficient concrete, for drainage or as a sub‐base in roads and on occasion as a decorative or esthetic element in pedestrian pathways in parks and landscaped grounds. In Spain, 54% of C&DW is ceramic‐based (CB‐C&DW). Since the use of such waste as recycled aggregate is not envisaged in Spanish legislation, it is presently stockpiled in landfills, an environmentally, technically, and economically detrimental procedure. The CB‐C&DW recycled at 12 Spanish waste management plants was assessed to determine the feasibility of its use as an alternative to pozzolans such as silica fume and fly ash presently added to cement during manufacture. The proportion of ceramic‐based material contained in this recycled waste varied from plant to plant. The effect of the ceramic‐based material content on the chemical and mineralogical composition, morphology, and pozzolanic activity of CB‐C&DW was explored in a more exhaustive study of two types of waste, one with 20 and the other with 100% ceramic‐based material content. In light of its chemical and mineralogical composition, morphology and lime fixation capacity, this type of C&DW was found to be apt for use as a pozzolan, and hence as a valid alternative for manufacturing more eco‐efficient cements.

Inclusion of construction and demolition waste as a coarse aggregate and a cement addition in structural concrete design

“…The 859.5 million tonnes of construction and demolition waste (C&DW) generated yearly in the EU alone [4] constitute the largest flow of discarded materials Europe-wide. That waste contains around 54 % by volume of fired clay-based, also called ceramic, materials [5]. Many EU countries are striving to reach 70 % valorisation of such waste by 2020 [6].…”

Use of ceramic industry milling and glazing waste as an active addition in cement

“…Fired clay industry waste is one of the new pozzolans explored by researchers. A number of prior studies on this material showed that fired clay of different origins has very promising pozzolanic properties because when fired at temperatures of 600°C‐900°C and ground to cement fineness, initially inert clay minerals acquire substantial pozzolanicity . The evaporation of chemically combined water at such temperatures and the resulting breakdown of the crystalline network of clay constituents induces the formation of an amorphous or vitreous material.…”

Construction and demolition waste applications and maximum daily output in Spanish recycling plants

“…Since the 1970s and especially in the last two decades, the international scientific community has researched extensively the viability of reusing C&DW as a raw material in the construction industry, primarily in cement (Asensio et al, 2016), concrete (Akhtar and Sarmah, 2018) and roads (Poulikakos et al, 2017), including studying its inclusion in the respective standards (LNEC-E471 (National Laboratory of Civil Engineering, 2006), EN 12620 (European Committee for Standardization, 2013)) (Tam et al, 2018) or formulating recommendations for its use (RILEM, 1994). If implemented, such measures would remove the barriers to the use of RA.…”