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The main aim of this paper was to investigate the possibility of obtaining green sustainable asphalt mixes by using two different recycled materials: reclaimed asphalt pavement (RAP) and crumb rubber (CR) from scrap tyres. With the numerous environmental and social benefits brought about, the use of modified hot mix asphalt and warm mix asphalt (WMA) mixtures should be the focal point of the construction policies in developing countries. Adaptation of this solution would result in an economical and sustainable green pavement with high resilience and safer workspace area with less fumes and odours for asphalt workers.

Experimental work-testing one control mix and modified design mixes, which have been modified either by RAP, CR, a WMA additive or any combination of the latter three products.

From the different test results, it can be rightly concluded that the addition of CR and RAP do enhance the properties of asphalt mixes to a varying degree. While CR adds a certain flexibility to the mixes and reduces the voids present, the presence of RAP has an amplified effect on stability, especially when coupled with rubberised WMA.

Marshall method still used as opposed to Superpave method in developing countries (Mauritius, Jordan here in).

A study for Tropical Island and its uniqueness to add to present knowledge.

The cementitious/chemical properties of the untreated CFA are dependent on the coal composition and previous burning conditions. The purpose of this paper is to investigate whether untreated CFA can efficiently reduce cement replacement and does not require further combustion treatment to be a viable cement replacement.

Two types of mixes: Type I concrete and PCFA (Type I and 30 per cent untreated CFA) concrete were batched and subjected to compressive strength tests and cyclic exposures of 5 per cent sodium sulphate (Na₂SO₄) and 5 per cent magnesium sulphate (MgSO₄), respectively.

PCFA mix was 41.1 and 35.21 per cent lower in strength compared to Type I at 28 and 56 days correspondingly. Continuous-sulphate-exposure resulted in slow but continued strength development for both mixes. However, the strengths of PCFA cubes exposed to cyclic sulphate and sulphate/magnesium salts continued to increase at a lower rate from their corresponding 28-day strength (rate of 18.7 per cent and strength 27.30 MPa in Na₂SO₄ and rate of 10.0 per cent and strength 25.30 MPa in MgSO₄) while Type I specimens subjected to the same exposure conditions experienced drastic reductions in strength (rate of −15.0 per cent and strength 33.21 MPa in Na₂SO₄ and rate of −23.4 per cent and strength 29.94 MPa in MgSO₄).

Results justify the need for additional tests essentially: at different percentage replacement of untreated CFA, fineness of materials, chloride environment and longer exposures, to address the cementitious properties of untreated CFA as cement replacement.

Treatment methods for fly ashes require undoubtedly additional resources, energy input and cost. This paper paves the way to define whether untreated CFA can be used as cement replacement in concrete.