Cleanliness of Mixed Fired Clay Bricks Coming from Construction and Demolition Waste

Abstract

Recycling of construction and demolition waste containing mixtures of fired clay and gypsum implies a separation process which aims to obtain individual fired clay and gypsum aggregates. This paper presents a method to quantify very small amounts of gypsum that still adhere at the fired clay bricks surface after the separation process. This may require a single or several steps. Leaching studies were carried out on mixed fired clay bricks and gypsum powder, by measuring the electrical conductivity of the water. Results show that maximum electrical conductivity of mixed fired clay and gypsum powder in contact with water can be correlated to gypsum content present in corresponding mixture. Therefore, electrical conductivity could be a method to evaluate the amount of gypsum which still remains at the surface of fired clay bricks after separation.

Recycling of bypass cement kiln dust in the production of eco-friendly roof tiles

“…The samples were exposed to a leaching test with a liquid-to-solid ratio of 10 l kg −1 . During the test, measuring cells are agitated [20].…”

Application of Wall and Insulation Materials on Green Building: A Review

“…Table 2. Evaluation items of green construction material labels in different countries [42,44,45,[47][48][49][51][52][53][54][55][56][57].…”

“…Particle boards Waste wood or wood waste from wood plant waste More than 90% [81] Medium density fiber (MDF) board Waste wood or wood waste from wood plant waste More than 90% [61] Wooden furniture Recycled particle boards, recycled MDF, or recycled materials from waste furniture, desks and chairs More than 90% of the wooden parts [82] Concrete aggregates (Material A) More than 80% of fine aggregates More than 50% of the coarse aggregates [55,83] Ceramic tile (Material A) 15~25% [84] Gypsum board Gypsum recovered after use, harmless gypsum in plant process More than 50% [85] Common bricks (Material A) More than 40% [54,86] Hollow concrete blocks (Material A) 20~50% (except for cement) [55,87] Compressed concrete paving units (Material A) 20~50% (except for cement) [52,55] Regenerated fiber cement boards Waste concrete materials, harmless inorganic waste, waste ceramics, glass and stone 50% (except for cement) [88] Lightweight concrete panels (Material A) More than 50% [82] Blended hydraulic cement Waste blast furnace slag, blast furnace dust, fly ash More than 40% [52] Granulated aggregate for decoration Recycled glass, ceramic pellets More than 70% [89] Permeable concrete paving blocks (Material A) More than 50% [8] Rubber paving block Reclaim rubber and all kinds of macromolecule material More than 80% [90] Synthetic stone (Material A) More than 60% [8] Concrete tile Coal ash, furnace dust, recycled aggregate and so on More than 25% [55,91] Green concrete (Material A) 20~50% [92] Autoclaved lightweight aerated concrete blocks (Material A) More than 60% [93] Terrazzo blocks and terrazzo tiles (Material A) More than 50% [91] Wood-plastic recycled composite Recycled plastic and wood materials More than 50% [82,94,95] Plastic floor Recycled plastic materials More than 30% [82] Material A: The surplus earth and stone of construction, industrial sludge, reservoir sludge, harmless inorganic waste, such as waste ceramics, waste glass, furnace powder, fly ash...…”