Dear Tehmina Ayub, please see this article:

Fresh and Hardened Properties of Fiber-Reinforced Rubber Concrete

By: J. Chris Carroll and Nicholas Helminger

I believe it's useful for you

best wishes

Try to get benefit from this literature overview:

Recycled Rubber as an Aggregate Replacement in Self-Compacting Concrete—Literature Overview

(Robert Buši´ et al. 2018)

For rubberized fiber concrete, preferable option is the used tire crumbed rubber. In that case you can use steel wire obtained from used tire, other options is the PVA fiber has shown better compatibility. Whereas about the content, up to 30% replacement by sand has shown better results, however, it depends on the specifications (target strength, fatigue life etc.)

According to the literature the the percentage was up to 30 % . But be careful with constant w/c the fluidity of cement concrete increased as the dosage increase so the compressive and flexural were decreased and the toughness increased

Please read following article for more information

Utilization of recycled crumb rubber as fine aggregates in concrete mix design

Author links open overlay panelCamille A.IssaGeorgeSalem

Thank you. I just requested authors to provide me paper.

For using rubber in concrete, we want to make sure to get proper bonding. For this you need to use bonding agent which will gives better results.

Do we really need bonding agent? I haven't found in literature about this thing. Could you please recomend any bonding agent with literature support?

Yes. Give me sometime. I will provide you literature support

coupling agent named “3-Mercaptopropyldimethoxysilane” used in one of the project.

fine crumb rubber can be opted as a replacement material with sand up to 20 %. Concrete with this much of percentages may give better results in terms of strength performance. Fibres like polypropylene or glass fibres can enhance tensile as well as flexure properties of resultant concrete...