Internal Curing - Conference Planning and Management

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Internal Curing - Conference Planning and Management

INTERNAL CURING

Using Prewetted Lightweight Aggregates

Improving Concrete Durability and

Sustainability Using Internal Curing

Presented to:

Better Concrete Conference – Ames, IA

November 1, 2012

Daron Brown

Technical Service Manager

Buildex, Inc.


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Extensive Lab Research

123 Citations as of

May 2012


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

NIST – Internal Curing “home page”

http://ciks.cbt.nist.gov/lwagg.html


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

ACI:

“supplying water throughout a freshly placed

cementitious mixture using reservoirs, via pre-wetted

lightweight aggregates, that readily release water as

needed for hydration or to replace moisture lost

through evaporation or self-desiccation [1]”

• Use fine aggregate to distribute water

• Help satisfy increased water demand from SCM’s

• Works even at moderate 0.40 – 0.48 w/cm


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

• Use fine aggregate to distribute water

• Help satisfy increased water demand from SCM’s

• Works even at moderate 0.40 – 0.48 w/cm


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

It’s All About the Distribution

Coarse LWA

Fine LWA

Henkensiefken (2008)


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Typical Desorption for LWA

- Virtually all moisture available at 94% RH

Castro 2011


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

ASTM C 1761: Specification for Lightweight Aggregate for

Internal Curing

- Balloted and accepted in June 2012


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

• Benefits

• Less shrinkage, less cracking

• Improved transport properties

• lower water absorption

• lower chloride permeability & penetration

• More hydration & SCM reaction

• less cement or more strength

• Results

• More durable structures achieving extended service life

• Improved economics

• Increased sustainability


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Less Shrinkage; Less Cracking

Byard (2010)


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Less Shrinkage; Less Cracking

Restrained Condition/73 o F Fall Curing Profile

Byard (2010)


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Less Shrinkage; Less Cracking

Restrained Condition/95 o F Summer Curing Profile

Byard (2010)


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Paving in Texas, Bridges in New York & Indiana

UP RR Intermodal Facility

Constructed 2005

250,000 yd 3 IC project low

slump pavement

NY: 9 built or under construction, 7 in design

Visual inspections

At 6 months one crack

At 5.5 yrs minuscule plastic or

drying shrinkage cracks

IN: 33 bridges


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Internal Curing vs. No Internal Curing

Highlands Ranch, CO – 92 o F ambient, 20% RH

No conventional curing


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Denver Water

Highlands Ranch, CO – 1300 yard slab pour

Change Order to include walls and columns


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Buchanan County, Iowa

“Launch Cast” Bridge

2’ thick slab


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Buchanan County, Iowa

“Launch Cast” Bridge

Iowa DOT Mix: C-4WR-C20-S20


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Buchanan County, Iowa

“Launch Cast” Bridge

With

internal

curing


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Buchanan County, Iowa

“Launch Cast” Bridge


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Buchanan County, Iowa

Conventional Cast-In-Place Concrete Bridge

- D-22 over Pine Creek

- DOT mix & Internal Curing

- Iowa Highway Research Board funding

- Spring 2013 ???


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Service Life Prediction

– NRC Canada

Cusson (2010)


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Initial & Life Cycle Cost

– NRC Canada

Cusson (2010)


INTERNAL CURING USING PREWETTED LIGHTWEIGHT AGGREGATE

Questions?

Daron Brown

Technical Service Manager

Buildex, Inc.

PO Box 77

Ottawa, KS 66076

(785) 242-2177

dbrown@buildex.com

www.buildex.com

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