“GREEN”Concrete Technology Katherine Chevrier

Concrete Mix Designs

3 Presentation name or chapter Date | You don’t have to be a Mad Professor!!!

What is Concrete?  Components  Concrete is a composite construction material, composed of cement, SCMs (fly ash, silica, slag), aggregate (coarse and fine), water and chemical admixtures  The Cementitious portion combined with water and admixtures is considered the paste which acts to bind the aggregates together as it hardens  Aggregates provide the skeleton which gives the concrete volume stability  Hardening process by hydration  Chemical reaction with water  The hardening of the paste is referred to the Hydration Reaction 4

5 Concrete Fundamentals – Ingredient Blending The % of ingredients blended within the design impacts the performance of the concrete and its intended use. Cementitous = cement + scm Grout / Paste = cementitous + water + admix Mortar = grout + sand Concrete = mortar + gravel Do not confuse the terms :

Concrete Design Fundamentals  Crack Resistance Horizontal Application (SOG)  Large sized CA (40mm/20mm)  High amount of CA in design  100% fracture or high amount of fracture in CA blend  Lower amount of %SCM replacement  Smooth Finish Vertical Application (Walls)  Smaller sized CA (14mm)  Lower amount of CA in design  Round CA or round/fracture blend (30%)  Higher amount of %SCM replacement  Special Density Concrete (Thermal conductivity/Radiation shielding)  Normal weight concrete 2200 to 2400kg/m3  Lightweight concrete as low as 240kg/m3 (cork/pumice/beads)  High Density Concrete up to 6000kg/m3 (magnetite/iron) 6 The right design for the right application  High Mpa Mixes (high rise)  Smaller sized CA  Low amount of CA in design  Round/fracture blend  High amount of %SCM replacement  Low W/C ratio / HRWR  Slow Strength Gain / hydration stabilizer  Tower Boom Pump Mixes  Smaller sized CA (14mm)  Lower amount of CA in design  Round CA or low fracture blend (20%)  Higher amount of %SCM replacement  SCC  High SCM  High amount of HRWR

Concrete Design Fundamentals 7 Green Designs

Cement and Cementing Materials – Better Environmental Options

Cement 9 Manufacturing Clinker

Cement 10 Types of Cement Defined by CSA A3000  Type GUGeneral Use  Type GuLPortland Limestone  Type HEHigh Early Strength  Type MSMod sulphate resistance  Type HSHigh sulphate resistance  Type MHModerate Heat of Hydration  Type LHLow Heat of Hydration  GU Up to 5% interground limestone  GUL or PLC 6 to15% interground limestone 10% less C02 emissions

Supplementary Cementing Materials 11 Uses in Concrete for Greener Options Not “The Devil” if Used Properly At the RIGHT Dose In the RIGHT Design For the RIGHT Application SCM

Supplementary Cementing Materials 12 Effects on concrete Fly ash, slag, silica fume are materials that when used in conjunction with Portland cement contribute to the hardened concrete through hydraulic or pozzolanic activity. Pozzolanic activity is when a material reacts with the calcium hydroxide released by the hydration of portland cement to contribute to the concretes performance and durability Bi – products of industry manufacturing Coal – power plants Iron ore - iron Silicon

Supplementary Cementing Materials  Improved Placing/Workability  Less Bleeding  Better pumping  Lower heat of hydration  Lower temperature differentials  Improved permeability  Reduced CO2 emissions  Less cement required  Improved Strength Gain  Allows lower water to cement ratio  Reaction with cement hydration  Crack control  Stronger/resistant pores in surface paste 13  Reduced landfill waste  Reusing an industrial by product  Reduced CO2 emissions  Less cement required  Slower set times  increased working hours  premature surface drying can occur in dry or windy weather  tendency to finish too soon which can cause delamination  It is important not to seal the surface to allow for delayed bleeding  Slower strength gain  Slow down production  Increase stripping times cement mixes  Inconsistencies in products  Changes in carbon content can create fluctuations in air contents

Water & Aggregates Reduce Reuse Recycle

Recycled Water – Non Potable – Grey Water  Settling Pond  Wash water moves through a series of ponds settling out solids/contaminates  Water from the final pond is reused in concrete at a replacement % of potable water  Settlement slurry must be pumped, removed and disposed of  Recyclers - Enviroports  Wash water is deposited into an agitated tank, aggregate is augured out and reused (e.g.. CDF mixes)  Water is then deposited through agitated holding tanks, SG’s are read and displayed on batch panel, water is reused in concrete at a replacement % of potable water  Water must be continuously used to keep SG’s down so it is safe to use in the concrete. Expensive and high maintenance 15 Filter and Reuse – Recycle all Material = Reduce Intake

Recycled Water – Non Potable – Grey Water 16 Control and Testing “Water of unknown quality, including treated wash water and slurry water, shall not be used in concrete unless it produces 28 d concrete strengths equal to at least 90% of a control mixture. The control mixture shall be produced using the same materials, proportions, and a known acceptable water. The mixing water in question shall be assessed on a semi-annual basis or more frequently if any change in water quality is suspected. The mixture used to assess the mix water shall be designed for a strength of 25 Mpa or greater at 28 d, and utilize a representative sample of the water in question”

Recycled Aggregate in BC Concrete 17 The Future – Captains Log October 22 Year 2015…..  We are not there yet  Currently working on testing and trialing  Getting recycled aggregate usage acceptable in standards and specifications  Recycling Aggregate from demolished concrete structures  Concrete is crushed, screened, tested  Recycled aggregate is then reused in concrete products at a replacement % of virgin material To make progress You need to push progress

Green Concrete 18 An Industry Effort Today’s modern concrete is a lot different than yesterdays mud Concrete has changed to make bigger structures, longer bridges, higher buildings Concrete can now achieve great strengths, get stronger faster, flow farther and place easier through the tightest steel and at any density Concrete can replicate any medium in appearance and can create the most wondrous structures Concrete has changed to allow us to adapt in a new civilization, to house and transport our greater numbers, to make our lives easier and to surround us in beauty We collectively have accepted the difficulties of modern chemical concrete to suit our needs and convenience when needed Now lets collectively accept and work together as an industry to produce and use more “GREEN” concrete to suit our environment

The End 19 Thank You