Characterization of Jordanian Volcanic Tuff and its Potential Use as Lightweight Aggregate

In the current study, Jordanian volcanic tuff (JVT) as a lightweight aggregate is experimentally evaluated. Two types of JVT areinvestigated, namely zeolitic volcanic tuff (ZT) and the black volcanic tuff (BT), from two volcanic eruptions at Al Hala area insouthern Jordan. They are investigated in terms of specific gravity, bulk density, porosity, water absorption, and slake durabilityusing the Los Angeles method. Ten mixtures were prepared using the typical crushed limestone aggregate at first, then volcanictuff aggregate was used as a replacement for the limestone aggregate at the various ratios of 25, 50, 75 %, followed by a totalreplacement of 100 % volcanic tuff aggregate. Compressive strength, abrasion, indirect tensile strength, flexural strength, ultra-sonic velocity, thermal conductivity, permeability, specific gravity, shear strength and modulus of rupture tests are conductedon the prepared concrete samples.The results of aggregate characterization indicate that specific gravity ranges from 1.8 to 1.92 for BT and from 1.98 to 1.98for ZT. Bulk density (kg/m3) ranges from 1189 to 2012 for BT and from 2010 to 2110 for ZT. The two samples possess goodporosity with a value of 0.605 (60.5 %), while water absorption for the two samples ZT and BT is 8.7 and 10.2 %, respectively.The above results showed good specifications for JVT to be used as lightweight aggregate. An experimental program based ontesting several standard cubes containing different percentages of volcanic tuff as coarse aggregate was prepared.The results indicated that the best compressive strength obtained is for the mixture of BTC4 as 41 Mpa and with a correspond-ing density of 1.85g/cm3.Black volcanic tuff and zeolitic tuff concrete are considered to be light weight concrete compared to the normal weight concrete.The main distinguished characteristic of lightweight concrete is its low density and its higher compressive strength as well.