effect of curing methods on the properties of

8/7/2019 EFFECT OF CURING METHODS ON THE PROPERTIES OF

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EFFECT OF CURING METHODS ON THE

PROPERTIES OF PLAIN AND BLENDED CEMENT

CONCRETES

Presented by

D.V.L.HARSHITHA

I/II M.Tech, Engineering Structures

Roll No: CE 091030



CONTENTS

METHODOLOGY OF RESEARCH

MATERIALS

SPECIMEN PREPARATION

EXPOSURE

TEST TECHNIQUES

R ESULTS

PLASTIC SHRINKAGE STRAIN

DRYING SHRINKAGE STRAIN

COMPRESSIVE STRENGTH

PULSE VELOCITY

DISCUSSION

CONCLUSIONS



INTRODUCTION

Curing of concrete is very essential for its strength gain and

durability.

Proper curing becomes very difficult under hot weather conditions

as low humidity and high ambient temperature greatly assist in the

evaporation of the mix-water



Curing becomes even more important if it contains supplementary

cementing materials, such as fly ash, ground granulated blast furnace

slag, or silica fume

Concrete is mostly cured by covering it with wet burlap. In some cases

it is also done by coating the freshly cast surface with a curingcompound

y Acrylic compounds

y water based compounds



MATERIALS

y Plain Cement

y very fine fly ash (VFFA)

y silica fume

y fly ash

y Type 1 cement

y Crushed limestone

y Dune sand



Constituent (wt.%) Type I cementVery fine fly ash

(VFFA)Silica fume Fly ash

SiO2 20.52 53.5 93.7 52.8

Al2O3 5.64 34.3 0.16 34.3

Fe2O3 3.8 3.6 0.12 3.6

CaO 64.35 4.4 0.65 4.4

Mgo 2.11 1 0.39 1.1

SO3 2.1 -- 0.23 0.1

Loss on ignition 0.7 -- 5.14 0.8

K 2O 0.36 0.8 0.02 0.5

Na2O 0.19 -- 0.02 0.4

Na2O equiv 0.43 -- --

MnO2 -- -- 0.1

TiO2 -- 1.7 -- 1.6

C3S 56.7 -- -- --

C2S 16.05 -- -- --

C3A 8.25 -- -- --

C4AF 11.56 -- -- --



The concrete mixtures were proportioned on a weight basis.

The following parameters were kept constant in all the

mixtures

Cementitious material content: 370 kg/m3.

Coarse/fine aggregate ratio: 1.64.

Effective water to cementitious materials ratio: 0.45.



Specimen preparation

Specimen size (mm) Property

100 × 100 × 300 Plastic shrinkage

100 × 100 × 300 Drying shrinkage

100 × 100 × 100 Compressive strength

100 × 100 × 100 Pulse velocity

50 × 100 × 300 Moisture retention



The concrete specimens were tested for the following:

Plastic shrinkage.

Drying shrinkage.

Pulse velocity, according to ASTM C 597.

Compressive strength after 3, 7, 14, 28 and 90 days,

according to ASTM C 39.



Results

Plastic shrinkage strain in the plain cement concrete specimens.



Drying shrinkage strain



Curing Efficiency Index (CEI)



The CEI varied from 86% to 91% in the concretespecimens cured by the application of acrylic-based

curing compound.

In the concrete specimens cured by applying thewater-based curing compound the CEI ranged from

84% to 89%

The CEI with regard to the pulse velocity was in the

range of 95±97%, indicating that the application of

either acrylic-or water-based



CONCLUSIONS

The curing compounds investigated in this study, namely

acrylic-and water-based, were effective in decreasing theplastic and drying shrinkage strain in both the plain and the

blended cement concretes

The curing compounds investigated, namely the acrylic-and

water-based curing compounds were effective in retaining

the moisture required for the development of denseness andcompressive strength of both plain and blended cement

concretes



The data developed in this study have indicated that curing

compounds could be utilized for curing plain and blended

cement concretes without any negative effect on plastic and

drying shrinkage and strength development and denseness

This is a positive implication for regions with scarcity of water or in situations where curing with water is difficult.

Among the two curing compounds investigated, acrylic-

based curing compound performed better than the water-

based curing compound.



REFERENCES

www.wikipedia.com Concrete technology by M.S.SHETTY

effect of curing methods on the properties of

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