Effect of Adding Scoria as Cement Replacement on Durability-Related Properties

Abstract

A lot of reinforced concrete (RC) structures in Syria went out of service after a few years of construction. This was mainly due to reinforcement corrosion or chemical attack on concrete. The use of blended cements is growing rapidly in the construction industry due to economical, ecological and technical benefits. Syria is relatively rich in scoria. In the study, mortar/concrete specimens were produced with seven types of cement: one plain Portland cement (control) and six blended cements with replacement levels ranging from 10 to 35 %. Rapid chloride penetration test was carried in accordance with ASTM C 1202 after two curing times of 28 and 90 days. The effect on the resistance of concrete against damage caused by corrosion of the embedded steel has been investigated using an accelerated corrosion test by impressing a constant anodic potential. The variation of current with time and time to failure of RC specimens were determined at 28 and 90 days curing. In addition, effects of aggressive acidic environments on mortars were investigated through 100 days of exposure to 5 % H 2 SO 4 , 10 % HCl, 5 % HNO 3 and 10 % CH 3 COOH solutions. Evaluation of sulfate resistance of mortars was also performed by immersing in 5 % Na 2 SO 4 solution for 52 weeks. Test results reveal that the resistance to chloride penetration of concrete improves substantially with the increase of replacement level, and the concretes containing scoria based-blended cements, especially CEM II/B-P, exhibited corrosion initiation periods several times longer than the control mix. Further, an increase in scoria addition improves the acid resistance of mortar, especially in the early days of exposure, whereas after a long period of continuous exposure all specimens show the same behavior against the acid attack. According to results of sulfate resistance, CEM II/B-P can be used instead of SRPC in sulfate-bearing environments.

Laboratory Simulation of Corrosion Damage in Reinforced Concrete

“…While several studies had employed a constant voltage accelerated corrosion regimes (Pellegrini-Cervantes et al 2013;Deb and Pradhan 2013;Kishore Kumar et al 2012;Lee et al 2000;Al-Swaidani and Aliyan 2015), several others had also used constant current accelerated corrosion regimes (Talakokula et al 2013;El Maaddawy et al 2005;Kashani et al 2013;El Maaddawy and Soudki 2003;Pritzl et al 2014). One of the studies (El Maaddawy and Soudki 2003) focused on the effectiveness of the impressed (constant) current technique using current densities in the range of 100-500 lA/cm 2 to simulate corrosion of steel reinforcement in concrete.…”

Production of Greener Recycled Aggregate Concretes Using Local Supplementary Cementing Materials

“…The formation of more hydration products as volcanic scoria hydrated might block the ingress path of chloride ions, thus enhancing the resistance to chloride penetration [3]. Furthermore, the results obtained clearly indicate that the water permeability data cannot effectively be used to predict the concrete resistance to the chloride-ion penetration and vice-versa, especially when limestone filler is used in concrete.…”

“…The corresponding increase of the 7 days-cured concrete was 10%, 15% and 20% for the concrete mixes prepared with LF, VS and LF+VS, respectively. This could be attributed to the more compacted concretes when adding fine and pozzolanic additives [3,4]. The relationship between the compressive strength and the modulus of elasticity was established, as shown in Fig.…”

“…The replacement of Portland cement by SCMs could significantly minimize the quantity of CO2 released and the energy consumed [3,4]. Furthermore, the addition of SCMs has been found to improve the properties of RAC [5][6][7][8][9][10].…”

Effect of Scoria on Various Specific Aspects of Lightweight Concrete

“…Several researchers have investigated the effects of scorias as replacements for cement, namely with respect to the mortar toughness, cement fraction (Al-Swaidani and Aliyan 2015;Bondar 2015;Lotfy et al 2015;Ghrici et al 2007;Rabehi et al 2014), the fabrication of granulate forms for lightweight concretes (Mouli and Khelafi 2008), and thermal activation (Ezziane et al 2007). Most studies have shown that scorias are economically sound and ecologically friendly building materials (Vlček et al 2014).…”