Abstract
This paper analyses the properties of concrete produced with Natural Lightweight Aggregates from Cameroonian volcanic scoria VS. Two groups of concretes with VS were prepared. A first concretes group produced with a natural sand from Covilhã-Portugal was cast in cubic specimens (150×150×150mm) and a second with a natural sand from Rabat-Morocco was cast in cylindrical specimens (160×320mm). The concrete mechanical properties were evaluated by non-destructive tests (NDT) and destructive test (DT). Schmidt Rebound Hammer (SRH) and Ultrasonic Pulse Velocity (UPV) were performed to determine the concrete rebound number (RN) and the concrete dynamic modulus of elasticity (Ed) at 28, 56 and 90 days. The concretes compressive strength at 28, 56 and 90 days on cylindrical specimens has been determined using DT method and predict by empiric expressions, normally applied for normal concretes, in function of RN or/and UPV. The results show that, at ages from 28 to 90 days, the concrete compressive strengths increase by 27.42–35.36%, the RN increase by 5.2–22.3%, while the UPV increase only by 4.2–7.4%.A concrete compressive strength model fc28 was proposed considering the effect of water-binder (W/B) and aggregate-binder A/B ratios, matrix volume Rm, VS aggregate VVSA and sand Vs, the densities of the aggregates and the characteristic resistance of the cement RC. It has been concluded that W/B, A/B, VVSA and RC showed more influence on the prediction model than Vm and Vs. Finally, it was concluded that concretes with VS from Cameroon can be used as structural or semi-lightweight concrete.
Published Version
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