Sustainable concrete design and construction

Sustainable Concrete Design

• ·

• Lowering CO2 in Construction

• CO2 Construction Audit

• Elegance in Architecture

David Bennett

Architectural Concrete Consultant

Picture a Glass of Latte

What’s the Embodied C02?

• Raw Material

• Production

• Packing

• Transport

• Shop

• Hot Water

• Coffee Container

• Milk

• Sugar

Concrete and C02It’s just like a good cup of coffee

Expresso, Americano, Latte, Macchiato, Mocha

Insitu, Precast, SCC, GRC, Ductal, Rammed

Discuss

C02 and Concrete Construction

• Cement

• Aggregates

• Ready Mix

• Rebar

• Formwork /Temporary Work

• Plant & Machinery

• Labour

Concrete

Cement is one sixth of concrete

kg C02/tonne

• OPC range 930 > 760

• GGBS 54

• PFA 4

• Rocktron 50

Persistence Works

Lowering Cement C02 by 50%

• Blend OPC with GGBS/PFA

• Carbonation Benefits of OPC

Aggregates are 80% of Concrete

Aggregates kg C02/tonne

• Natural Washed - 4

• Natural Crushed - 4-10

Synthetic Aggregates

• Lytag Sintered PFA 60

• Liapor (expanded shale) 12

Typical Concrete Mix

Constituents

kgC02/m3

OPC 180 kg Ribblesdale 137

GGBS 180 kg C & M 8

Sand 750 kg Lea Valley 3

Gravel 1200 kg Thames Estuary 5

Water 180 kg Thames Water 0

Admixture ignore

Embodied kg C02/m3 153

CO2 of Wood

Captured CO2 = 1.84 x density

Embodied CO2

Process plywood 670 kg C02/tonne

Wisa – birch phenolic faced

18mm thick 29 kg CO2/m2

(assumes the wood is carbon zero)

Formwork

Temporary Support/

Falsework

Disposable Items

• Form Face Ply

18mm thick

• Plastic Cones

• Tie Rods

The Form Face & Sustainable

Design

• Select Material for a Good Finish

• High Reuse Factor

• FSC Grade

• Re-use in Permanent Architecture

• Responsible Design

Rebar C02

kg C02/tonne Total

Two Stage Process

1. Coil Manufacture 422

2. Fabrication

a) Bar 63 485

b) Mesh 88 501

Celsa/ BRC Auditincludes production , staff travel and transport

Concrete Quality and

Aesthetic

• Visual Concrete Specification

• the choice, the mix, the form, the finish

Get it right!

Thrifty Beeches

Spedant Works

Kew Herbarium

CHUR House

The C02 Construction Audit

Four Buildings Assessed

two concrete, two steel

• Bill of Quantities

• Embodied C02 of Materials

• Plant/Machinery/Labour

Some Anomalies Some references are distorted

• Resin, Polyurethane, Paint, PVC

resolve micron/m2

• Structural Steel

new or recycled? check

• Lightweight Lytag Concrete

high C02/m3

RECONCILE them

Construction Audit Examples

• Substructure

• Superstructure

• External Cladding

• Finishes

• Mechanical Ducting

Building CO2 Audit Summary

Element M4C3 % M4S3 % M4C7 % M4S7 %

Substructure 136 10 95 4 254 9 160 3

Superstructure 350 27 1348 59 904 31 3411 63

External cladding 263 20 267 11 532 18 545 10

Finishes 432 33 433 19 893 31 911 1

M&E: Fully air conditioned 59 4 59 3 137 5 137 3

Plant & labour 83 6 89 4 190 6 189 4

Total (av.) 1322 100 2291 100 291 100 5353 100

Tonnes CO2

Building CO2 Audit Summary

Possible reductions in CO2 for lean solution

Element M4C3 % M4S3 % M4C7 % M4S7 %

Frame - na -768 na -1972All recycled steel

M&E;

a) eliminate suspended -60 na -149 na ceiling

b) Reduce ductwork -53 na -124 na

Public transport -77 -83 -183 -182

Total CO2 reduction -190 -14 -851 -37 -455 -16 -2154 -40

Total C02 Design Solution

• Minimise Construction C02

• Utilise Thermal Mass for Long Term

Energy Reduction

Lower Total C02 Emissions

Concrete is just like a good coffee -

Make it the low C02 blend!