7/23/2019 Brochure - Calcium Chloride in Portland Cement Concrete

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Calcium Chloride in Portland Cement Concrete

Still the Most Effective Concrete Accelerator

Application Information

Introduction

It has long been known that curingconcrete during cold weather canresult in an inferior product withsubstandard properties. Curing alsotakes much longer, adding to job costsand extending the time before theconcrete surface can be used.Although there are many types ofaccelerators, calcium chloridecontinues to be one of the mostpreferred. No other accelerator hasbeen used so successfully for so long.

Why use Calcium Chloride?

Calcium chloride (CaCl2), has theability to accelerate cement hydrationand reduce set time by as much astwo thirds. Research has shown thata 2% addition rate has an equivalentcure strength at 50F as plainconcrete at 70F. Set times below50F will be longer, but the acceleratedcure rate will still be greater than thatof plain concrete.

In addition to the importantcontributions of cold weather

protection and early strength ofconcrete, calcium chloride providesother benefits as well:

Improves workability...regardless ofmixture design, less water isrequired to produce a given slumpwhen calcium chloride is used.

Improves strength of air-entrainedconcrete...calcium chloridecompensates for the reduction instrength with a higher cement factorconcrete.

Reduces bleeding...this is due to

the early stiffening produced byacceleration and allows earlier finalfinishing.

These advantages combine toproduce better quality concretefaster. Concrete acceleration withcalcium chloride greatly facilitatescompleting jobs as quickly andeconomically as possible.

Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow

Refer to the back page for guidelines on the use of calcium chloride in Portland cement

concrete. For more information, visit our web site at www.dowcalciumchloride.com, or

contact The Dow Chemical Company Customer Information Group at 1-800-447-4369.

References:1 "Effect of Calcium Chloride on Portland Cements and Concretes." Paul Rapp,

Proceedings, Fourteenth Annual Meeting, Highway Research Board, (1934)2 "Measuring the Rate of Hardening of Concrete by Bond Pullout Pins." T.M. Kelly and

D.E. Bryant, Proceedings, ASTM, Volume 57, (1957)

Figure 1. Set Time Reduction with CaCI2 Addition1

Figure 2. Concrete Hardening Rate with CaCI2 Addition2

Hours

Pinbondstrength(psi)

SetTime(hours)

Addition Rate

7/23/2019 Brochure - Calcium Chloride in Portland Cement Concrete

2/2TMTrademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow Form 173-01714-606XQRP

Notice: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one

location to another and may change with time, Customer is responsible for determining whether products and the information in this document are

appropriate for Customers use and for ensuring that Customers workplace and disposal practices are in compliance with applicable laws and other

governmental enactments. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL

IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

Published June 2006.

Guidelines for Using CalciumChloride in Concrete

Calcium chloride used as anadmixture for concrete should meetthe requirements of ASTM D98.

The amount of calcium chloride usedshould not exceed 2% (Table 1) andpreferably, should be added in solutionform to the aggregates in the mixerdrum or as a portion of the mixingwater, reducing the total mixing waterrequired by the amount of solutionbeing used.

When ready mixed concrete is used,calcium chloride should be added atthe plant site if the concrete is to bedischarged within one hour after thestart of mixing. Otherwise, it shouldbe added at the job site, mixing for atleast three minutes or 30 revolutionsof the mixer, whichever is longer.

If dry calcium chloride is used, itshould be added free of lumps to theaggregates in the mixer drum duringmixing, or to the mixed concrete justbefore discharge.

Concentrated calcium chloride shouldnot come into direct contact with drycement as it may cause flash set.

For best results, calcium chlorideapplication rates should vary withtemperature as follows, (see Table 1):

1. >90F no more than 1%2. 70F to 90F 1.0 to 1.5%3.