EFFECT OF WATER REDUCING CONCRETE ADMIXTURES
ON THE PROPERTIES OF CONCRETE
29th Our World in Concrete and Structures (OWICs) - 2004
Saeed Ahmad*, University of Engineering & Technology, Taxila, Pakistan
Attaullah Shah, Allama Iqbal Open University Islamabad, Pakistan
Karamet Ali*, University of Engineering & Technology, Taxila, Pakistan
Water reducing Concrete admixtures and Superplasticiser are widely used to
improve the mechanical and structural properties of fresh and hardened concrete. These admixtures are more frequently used in pre-stressed concrete, slender components with congested a nd densely packed reinforcement, beams and slabs pre-cast elements and long slender columns.
In this research two types of water reducing agents of Polymer and Modified
Lignosulphonate base conforming to ASTM C-494 type C and ASTM C 494-81 type A respectively have been used. Four nominal ratios of 1:1 :2, 1:1 .25:2.5, 1 :1.5:3 and1 :2:4 were used for mix proportioning of concrete constituents by weight. The water cement ratios were maintained as 0.50, 0.55 and 0.60 to study the effect of these admixtures on various properties of concrete. The dosage of admixtures has been adopted as constant @ 0.80 % by weight of cement. The effect of the addition of admixtures on the workability, water reduction, compressive strength, tensile strength and modulus of rapture has been mainly observed in the research.
The results have shown substantial improvement in the properties of concrete
after use of the admixtures. The Polymer based high range water reducer,
Superplasticiser has given more promising results as compared to the Modified
Lignosulphonate base water reducers.