Lightweight Self-consolidating Concrete with Expanded Shale Aggregates: Modelling and Optimization

Abstract

This paper presents statistical models developed to study the influence of key mix design parameters on the properties of lightweight self-consolidating concrete (LWSCC) with expanded shale (ESH) aggregates. Twenty LWSCC mixtures are designed and tested, where responses (properties) are evaluated to analyze influence of mix design parameters and develop the models. Such responses included slump flow diameter, V-funnel flow time, J-ring flow diameter, J-ring height difference, L-box ratio, filling capacity, sieve segregation, unit weight and compressive strength. The developed models are valid for mixes with 0.30-0.40 water-to-binder ratio, high range water reducing admixture of 0.3-1.2 % (by total content of binder) and total binder content of 410-550 kg/m 3 . The models are able to identify the influential mix design parameters and their interactions which can be useful to reduce the test protocol needed for proportioning of LWSCCs. Three industrial class ESH-LWSCC mixtures are developed using statistical models and their performance is validated through test results with good agreement. The developed ESH-LWSCC mixtures are able to satisfy the European EFNARC criteria for self-consolidating concrete.Keywords: expanded shale aggregates, lightweight self-consolidating concrete, multi-objective optimization, water to binder ratio, high range water reducing admixture, total binder content, statistical model.

Effects of Different Lightweight Functional Fillers for Use in Cementitious Composites

“…The reasons for such increased interest are its unique advantages over normal weight concrete such as reduction in dead loads leading to smaller structural member as well as foundation size, ease of the shipping and transportation in case of precast structural members, and reduced overall construction cost. In addition LWC offers excellent durability in chemical and frost attack with reduced permeability (Li 2011), greater fire resistance (ACI 216.1 1997) and better thermal insulation (ACI 213 2003). The unit weight of LWC lies in the range of 1200-1800 kg/m 3 (Li 2011) while for structural LWC in general ACI Committee 213 defines the range as 1120-1920 kg/m 3 (ACI 213 2003).…”

“…In addition LWC offers excellent durability in chemical and frost attack with reduced permeability (Li 2011), greater fire resistance (ACI 216.1 1997) and better thermal insulation (ACI 213 2003). The unit weight of LWC lies in the range of 1200-1800 kg/m 3 (Li 2011) while for structural LWC in general ACI Committee 213 defines the range as 1120-1920 kg/m 3 (ACI 213 2003). In order to achieve the desired unit weight with adequate mechanical properties, careful selection and efficient utilization of lightweight filler (LWF) materials is imperative.…”

“…Traditionally, different types of LWFs have been studied for their use in the cement-based composites such as expanded perlite (Demirboǧa et al 2001;Kramar and Bindiganavile 2010;Lanzó n and García-Ruiz 2008;Lu et al 2014), expanded glass beads (ASTM D790-10 2010; Bouvard et al 2007), shale (de Gennaro et al 2008;Ke et al 2009;Lotfy et al 2015), expanded polystyrene beads (Bouvard et al 2007;Miled et al 2007;Saradhi Babu et al 2005), expanded clay (Chandra and Berntsson 2002;Gao et al 2014) etc. and the unit weight has been successfully achieved within the stipulated guidelines.…”

Effect of Scoria on Various Specific Aspects of Lightweight Concrete

“…Relatively low-density aggregates can be obtained by substituting classical aggregates of sand and pea gravel with artificially lighter aggregates, such as expanded polystyrene beads (Chen and Liu 2004;Khedari et al 2003). Experimental works have shown that the characteristics of the aggregates are highly active in lightweight concretes, dictating the good mechanical, thermal, and acoustical performance of the final concrete (Lotfy et al 2015;de Sensale and Goncalves 2014;Chi et al 2003).…”

“…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).…”