ABSTRACT

Concrete is considered as main material in the construction industry. It is produced with the conventional ingredients , aggregates, cement and water. It is very strong in compression and weak in tension. Also it exhibits poor flexural toughness and post crack response. Generally steel fibers are very common in use. Fibers work in concrete as 'crackarrestors'. In Pakistan the use of fibers in concrete is very seldom and particularly fibers other than steel .This experimental study reports the effect of 'polypropylene fiber' on workability and fundamental strength properties of concrete. The concrete of 1:2:4 is cast with casted water­ cement ratio of value 0.5. the fibers extruded from the wheat bags available in local market.
.the fibers were used ' with uniform length of 2". The dosage of fiber content added from 0% to 2% with increament of 0.25% . A batch of normal concrete of same proportion but without fibers was also cast for the comparison purpose. Thus in all 09 batches were cast. The effect of fibers was studied in terms of workability , compressive strength and tensile strength . Workability is determined by slump test, whereas the cube and cylinder specimen of standard size were cast to evaluate the compressive and tensile strength respectively. Tensile strength is evaluated by indirect tensile strength method (splitting tensile strength of cylinders) in each case 05 specimen were tested to achieve the representative mean value. The results revealed the decrease in workability with the addition of fibers even converting control content of normal slump value in to no-slump concrete (zero slump). When fiber content added is 1.75% in concrete. The compression and tensile strength increased upto 1% of polypropylene fiber and then decreased. The polypropylene fibers are observed to be more effective in case of tensile strength than the compression strength at the same percentage of
fibers .