AGGREGATE, STRUCTURAL CONCRETE WITH AGGREGATE, AND METHODS OF FORMING SAME
An aggregate ( 12, 16 ) is disclosed as including a core ( 12 a ) made at least partly of biochar ( 10, 14, 26, 28 ), and a shell ( 12 b ) encapsulating the core, the shell being made of ordinary portland cement (OPC) and ground granulated blast-furnace slag (GGBS). Structural concrete ( 30 ) including such an aggregate is also disclosed.
1 . An aggregate including:
a core made at least partly of biochar, and
a shell encapsulating said core,
wherein said shell is made at least partly of a cementitious material and/or an alkali-activated material.
2 . The aggregate of claim 1 , wherein said cementitious material is at least one of cement, ground granulated blast-furnace slag (GGBS), waste glass powder, recycled powder, silica fume, and incinerator bottom ash (IBA).
3 . The aggregate of claim 1 , wherein said core is of a loose biochar with a loose bulk density from 100 kg/m 3 to 300 kg/m 3 , or of a densified biochar with a loose bulk density higher than 300 kg/m 3 .
4 . The aggregate of claim 1 , wherein said shell further includes at least a nano material.
5 . The aggregate of claim 4 , wherein said nano material is silica fume or nano silica.
6 . The aggregate of claim 1 , wherein said aggregate is carbon negative.
7 . The aggregate of claim 1 , wherein said aggregate is in pellet form.
8 . A structural concrete including at least the aggregate according to claim 1 and at least a matrix material.
9 . The structural concrete of claim 8 , wherein said matrix material is cementitious.
10 . The structural concrete of claim 8 , wherein said matrix material includes at least one of cement, GGBS, and silica fume.
11 . The structural concrete of claim 8 , wherein said structural concrete is carbon negative.
12 . The structural concrete of claim 8 , wherein said structural concrete is of a 28 d compressive strength of at least 30 MPa.
13 . A method of forming an aggregate, including a step (a) of encapsulating a core made at least partly of biochar by a shell made at least partly of a cementitious material, an alkali-activated material, or both a cementitious material and an alkali-activated material.
14 . The method of claim 13 , wherein said shell is made at least partly of cement and ground granulated blast-furnace slag (GGBS).
15 . The method of claim 13 , further including, before said step (a), a step (b) of compacting said biochar to increase its density.
16 . The method of claim 13 , further including a step (c) of applying at least a nano material on said shell.
17 . The method of claim 16 , wherein said nano material is silica fume or nano silica.
18 . The method of claim 13 , wherein said aggregate is formed by cold-bonding.
19 . A method of forming a structural concrete, including mixing at least the aggregate of claim 1 with at least a matrix material.
20 . The method of claim 19 , wherein said matrix material is cementitious.
21 . The method of claim 19 , wherein said matrix material includes at least one of cement, GGBS, silica fume, waste glass powder, recycled powder, and incinerator bottom ash (IBA).