Reactive pozzolana from Indian clays—their use in cement mortars

The use of water treatment plant sludge ash as a mineral addition

“…Kaolin clays are best for the production of thermally activated pozzolans, which display optimal activity after calcination between 600 and 800°C [28][29][30].…”

Influence of fired clay brick waste additions on the durability of mortars

“…They generally contain significant amounts of kaolinite (Al 2 O 3 Á2SiO 2 Á2H 2 O) that are transformed into metakaolinite upon calcination [3]. The faster reactions between amorphous silica and alumina from metakaolin with lime released from the cement lead to the formation of larger amounts of CSH and C 4 AH 13 , which promote several properties of the final mortar or concrete, namely high ultimate strength and low permeability [4]. The use of metakaolin and other pozzolanic materials, such as fly ash, silica fume, slag, rice husk ash, fired clay bricks and natural pozzolans, has also been shown to refine the pore structure, which results in reduced ionic mobility, consumption of calcium hydroxide and entrapment of alkalis in silica-rich hydration products, thus helping to suppress the deleterious expansion that results from alkali-silica reactions or exposure to chlorides and sulphates [5][6][7][8].…”

Physico-mechanical properties of composite cement pastes containing silica fume and fly ash

“…Pozzolana is a natural or artificial material containing silica in a reactive form. ASTM C618 [2] describes Pozzolana as a siliceous or siliceous and aluminous material which in itself possesses little or no cementitious value but will in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to exhibit hydrated cementitious properties [3,4]. The main hydration product of alite and belite in Portland cement is a calcium silicate hydrate (CSH) of colloidal dimensions, it is highly cementitious and represents about 60 to 65 wt.% of the total solids in a fully hydrated Portland cement.…”