ADMIXTURE

May 3, 2023 ADMIXTURE 1

ADMIXTURESPRESENTED BY,• AISWARYA. A. KUMAR• AMINA. RASAK• AMRITA. P. VIJAY• ANAGHA .VINOD• ANUPAMA. GANESH• ARDRA. S .ANIL

• ARDRA .SUSHEELAN• ANCHU. C. BABU


CONTENTS

RETARDER WORKABILITYAGENTS

WATER PROOFING ADMIXTURE

MICELLANEOUSADMIXTURE


1.RETARDERS

WHAT IS RETARDER?

• Retarder is an admixture that slowsdown chemical process of hydration

USES OF RETARDERS• Overcome accelerating effect of temperature in

hot weather concreting• Grouting oil wells[ if depth>6 km]• To obtain exposed aggregate look in concrete


AMAZING EXPOSED AGGREGATE ARCHITECTURE


COMMON RETARDERS

CALCIUM SULPHATE

GYPSUM[ used only when inspection and control available]

STARCH,COMMON SUGAR,ACIDS & SALTS


RETARDING PLASTICIZERS

1. All plasticizers and the superplasticizers by themselves shows certain extent of retardation.

2. Retarders are mixed with plasticizers or superplasticizers at the time of commercial production.

3. Such commercial brand is known as “RETARDING PLASTICIZERS OR RETARDING SUPERPLASTICIZERS”.


RETARDING PLASTICIZERS

4. Example for Retarding plasticizer is ASTM type D and example for retarding

superplasticizer is ASTM type G.

USES1.Long transportation2.During high temperature3.Avoid construction of cold joints

May 3, 2023 ADDMIXTURE 8

ASTM Categories of admixtures

1. Type A2. Type B3. Type C4. Type D5. Type E6. Type F

7. Type G

a) Water reducing admixtureb) Retarding admixturec) Accelerating admixturesd) Water reducing and retardinge) Water reducing and acceleratingf) High range water reducing

g) Water reducing,high range,retarding

ASTM C494 specifies the requirement for seven chemical admixture types they are:


2.WORKABILITY AGENTSWORKABILITY IS IMPORTANT UNDER;

Concrete to be placed in deep beams,thin sections,closely spaced reinforcement

Where special means of placement required[chute,tremie]

If concrete is harsh /For making high strengh concrete


MATERIALS USED AS WORKABILITY AGENTS

Finely divided materials

Plasticizers/super

plastizersAir entraining

agents


SHALL WE STUDY PROPERTIES OF FINELY DIVIDED MATERIALS???

• In appropiate quantity• Reduce rate and amount of bleeding• Increases strength of lean concrete• Maynot increase water requirement & drying shrinkage• Increases workability


EFFECTS IF WORKABILITY IS REDUCED…A PEEP

OUTPUT OF WORKABLE CONCRETE


3.WATER PROOFING /DAMPPROOFING ADMIXTURE

What is it?• WPA is seen in

powder,paste/liquid form• Consist of porefilling/ water

repellent materials

Types • Chemically active porefills• Chemically inactive porefills

Contains• Silicate of soda,aluminium

&zinc sulphates• Chalk,fuller earth,talc


SEE WHAT WILL HAPPEN IF DMA NOT USED…


HERE ARE THEY…..

Accoproof:• It is a white powder• Mixed at rate 1kg/ 1 bag of cement• It increases impermeability of concrete

structures


Natson’s Cement Water proofer•As name indicates it is a water proofing Admixture•Mixed at rate of 1.5 kg /bag of cement


con

TRIP –L-SEAL•It is a white powder•Addition decreases permeability•Produces rapid hardening effect


CICO

• Colourless liquid• Control setting time,increase strength,water

proofing


CEMENT:•It is a water proofing admixture•Recommended dose is 3% by weight of cement•Prevents effloresence and growth of fungi


Feb –mix-admix:•Light yellow coloured liquid•Claimed to impart water proofing quality to concrete•Increase workability and bond


FACING DIFFICULTY IN BYHEARTING THE NAMES

“HERE THE SOLUTION”

MNEMONICS


COMMERCIAL WATER PROOFING ADMIXTURES

• Arzok• Wet seal• Impermo• Luna –Ns-1• Omson’s “watse”• Water lock


WHAT REALLY IS A MISCELLANEOUS ADMIXTURE? HAVE A LOOK….

• Specialised admixtures which are not considered as chemical ,airentraining or mineral admixture

• Provides unique properties such pumping concrete, dampproofing,reduce shrinkage,colouring & avoid attack of fungi

COMPRISES OFORGANICS INORGANIC SYNTHETICS


AREAS WHERE MISCELLANEOUS ADMIXTURE IS APPLICABLE


MISCELLANEOUS ADMIXTURES

INTRODUCTION• Hundreds of commercial admixtures• They effect more than one property• They are sometimes ineffective & donot fill claims

of manufacturers• It is not intended to deal in detail about them ROUGH CLASSIFICATION

• Damp proofers[accoproof,cemet,trip-l-seal]• Surface hardeners[metal crete,ferrocrete

no1,metal crete steel patch, “ lispol N”]


TYPES OF SURFACE HARDENERS

METALCRETE: Metallic aggregate specially processed,size graded

iron particles Gives wear resistence,corrosion resistence,non

dusting,slipping concrete surfaceFERROCRETE NO 1: Surface hardener that makes concrete surface

compact,dense ,homogenous


METAL CRETE STEEL PATCH:• When added 20% by weight of cement

increases compressive strength and abrasion resistance

ARCONATE NO 1:• It is black powder • Composed of iron fillings• Surface hardener in concrete


MAGIC OF SURFACE HARDENERS


LISPOL -N


LET US REVISE…No Admixture Uses Examples

1. Retarders Lengthen setting time

CaSO4,gypsm,starch,common sugar,acids ,their salts

2. Workability agents Improves workability

Finely divided materials,Superplasticizers,Air entraining agents

3. Dampproofing agents

Retards moisture penetration in dry concrete

Accoproos,trip-l-Seal,cement,Feb-Mix-Admix

4. Miscellaneous admixture

Reduces shrinkage,fungi,corrosion

Metalcrete,Accoproos,Ferrocrete,Cico, “lispol N”


PREVIOUS UNIVERSITY QUESTIONS• SHALL WE PREPARE….

WHICH ONE YOU WANT???



REFERENCES• Note- shivkumar sir• Concrete technology -M S Shetty• Structural engg materials -N.Jackson,Ravindra .K.Dhir• Figures –google


Engineering

ADMIXTURE