Improving plastic shrinkage cracking of concrete using recycled waste rubber crumbs

الملخص EN

The objective of this study is to investigate a new technique to control plastic cracks due to concrete shrinkage by replacing a percentage of sand with fine crumbs of waste tires.

This technique utilizes a waste material to achieve crack control, which subsequently improves concrete durability.

Recycling used tires is another advantage, since they represent one of the most harmful waste materials causing a lot of pollution when recycled in an improper way.

An experimental program is designed to study the effect of rubber-sand replacement ratio (R-SR) on plastic shrinkage of concrete.

A total number of 20 specimens with different (R-SR) percentages are tested under different environmental conditions.

Specimens are divided into four groups of five specimens each.

Three percentages of (R-SR) of 3%, 5% and 7% by weight are used for the first three groups and the fourth one is the control group with no replacement.

The five specimens within each group are subjected to five different environmental conditions, which are : indoor condition, outdoor environment, wind effect, hot temperature and curing by covering with plastic sheets.

The study includes measurements of the first cracking time, crack width, percentage of cracking area and rate of evaporation.

The results are compared with the previous results available in literature using other types of additives.

Other 15.8- x 15.8 x 15.8 cm cube specimens are tested to investigate the effect of rubber crumbs on concrete strength.

Also,15 x 30 cm cylinders are used to draw the stress-strain curve for all (R-SR) percentages and normal concrete.