Properties of crumb rubber concrete paving blocks with and without facing layer

This paper presents a recent study on the investigation of recycled waste tyre (crumb rubber) as aggregate in the production of concrete paving block (CPB). A series of tests were carried out to determine and compare the properties of crumb rubber CPB prepared with and without facing layer. The results showed that the crumb rubber CPB without facing layer had little effect on the dry density, compressive strength, flexural strength, sound absorption and skid resistance. However, the abrasion index was higher for the specimens without facing layer. Using 1-3 mm and 1-5 mm crumb rubber as the replacement of fine sand for face layer and coarse sand for body layer, respectively at the level of up to 30 %, CPB with 28-days modulus of rupture of not less than 2.75 MPa can be produced without facing layer, while 2.54 MPa for the CPB with facing layer