Density of LWAC samples, where a part of EG aggregate is replaced by crushed expanded polystyrene waste, ranges between 225 and 309 kg/[m.sup.3] (Fig.
A partial replacement of EG aggregate by crushed expanded polystyrene waste, results in relative density decrease by 9, 10 and 8% respectively, comparing with LWAC samples only with EG aggregates which density was assimilated to 100% (Fig.
Many studies show that LWAC samples do not have high strength characteristics (Laukaitis et al.
As reported by Mehta and Monteiro , slump value for acceptable workability of LWAC ranges from 50 to 75 mm.
However, for an artificial LWAC, the ratio of 7 to 28 days compressive strengths was found between 76 and 87% .
Neville  reported equation (7) for pelletized blast furnace slag LWAC, with cube compressive strength in the range of 10 to 65 MPa.
(iii) Studies on the effect of hybrid fiber mechanical properties of LWAC
are warranted based on recent advancement in this area.
The improvement in the mechanical properties of LWAC depends on the oven-dried density, water-to-cement ratio, addition of other binder materials, aggregate content, and particle size [5, 6].
Mehta and Monteiro  reported that the LWAC with a slump value of 50-75mm is similar to normal weight concrete with a 100-125mm slump value.
Thus, higher strength-to-weight ratio, better tensile strain capacity, and lower density, which reduce dead loads in construction, are the main benefits from its use of LWAC [13-16].
However, little research has been done on the durability of LWAC with mineral admixtures, not to mention the combination of several types of mineral admixtures [12, 32, 33].
(vii) Both the splitting and flexural tensile strengths of the OPSGC showed acceptable values for LWAC