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4.7.7 Green Concrete
• There are three types of green concrete including – functional concrete– eco-concrete – recycled concrete
• In eco-concrete there are– permeable concrete– virescence concrete – sound absorption concrete
• Functional concrete has been introduced in the previous sections. We will focus on – virescence concrete– recycled concrete
Introduction
Virescence Concrete
• Virescence concrete is suitable for plant, vegetation and its products.
• There are 3 types: – Virescence concrete with holes
• It is designed to leave holes in the block for plant
– Virescence concrete with connected pores• It contains connected holes to provide spaces for root gro
wth and nutrient absorption
– Virescence concrete with holes in multilayers• It is made out of concrete with holes added by cavities an
d multilayers
Fig.4.7.12 Structure of Green Concrete
Fig.4.7.13 Virescence Concrete with Holes in Multilayers
• The upper layer is concrete with holes and cavities but the lower layer is concrete with holes not cavities.
• The two layers are glued together to form the space for earth filling.
• It is applied in parts, which has no direct connection with earth, for example, on the balcony in apartment buildings and top of the wall of the yard in the city.
• It can enlarge the green area in the city and make it more beautiful.
Virescence Concrete with Holes in Multilayers
Recycled Concrete
• Recycled concrete refers to the concrete whose aggregate or part of aggregate are made of recycled aggregate.
• Lots of waste will be produced when buildings are torn down.
• They take up much room and bring unhealthy effects on the environment.
• They can be processed by washing, cracking and setting to produce concrete aggregate called recycled aggregate.
Tab.4.7.12 Definitions of Architectural
Waste in Foreign Countries Country Definition
Canada Construction waste: waste in every phase
Japan
Building Cube Sand and stone dug up can be recycled
Building waste
Recycled: concrete, damp concrete, silt, paper, metal and used wood
Non-recycled: poison waste, disseminated
USA
Unpolluted solid waste from cleaning of new construction, maintenance, reconstruction, tear-down, farm clearing-up, public property maintenance and seasonal or natural disasters.
Recycled aggregate
• Process: Scrap the aggregate then crack with jaw
crusherThe distance between jaw boards is sim
ilar with that of natural coarse aggregate
• Features:lower than natural aggregate specific
gravityhigher water absorption
• Standard: Referred to the requirements of natural aggr
egate (JGJ53-92)
Recycled aggregate
Fig.4.7.14 Natural and Regeneration Coarse Aggregate Gradation Curve
020406080100
0 5 10 15 20 25 30
(mm)筛孔尺寸
(%)
通过
百分
数RCA1RCA2RCA3NA1
Fig.4.7.15 Ordinary Concrete and Regeneration Concrete Strength Curve
01020304050
0 10 20 30 40 50 60 70 80 90 100
( )龄期 天
(MPa)
强度
N50000R50000N60000R60000N70000R70000
Fig. 4.7.16 Fly Ash-added Recycled Concrete Strength Curve
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100
龄期(天)
MPa
强度
() N60000
R60000R61000R62000R63000
Chapter 4