Development of mix proportions of geopolymer lightweight aggregate concrete with LECA M. Priyanka a,⇑ , M. Karthikeyan a , M. Sri Rama Chand b a Department of Civil Engineering, VFSTR, Vadlamudi, Andhra Pradesh, India b Department of Civil Engineering, Sree Chaithanya College of Engineering, Karimnagar, Telangana, India article info Article history: Received 15 December 2019 Received in revised form 9 January 2020 Accepted 11 January 2020 Available online xxxx Keywords: Geopolymer concrete Light weight aggregate Light weight aggregate concrete LECA Compressive strength abstract Light weight Geopolymer concrete (LWGPC) is an innovative material which combines both the advan- tages of light weight concrete and Geopolymer concrete. This concrete provides eminent solution to decrease the self-weight of a structure while using zero percent cement concrete materials and increase the scope of Geopolymer concrete (GPC). This study investigates the strength of fly ash based geopolymer concrete produced with Lightweight Expanded Clay Aggregates (LECA). Twenty concrete mixes were pre- pared to get an appropriate mix design for LWGPC. A mixture of sodium hydroxide and sodium silicate with 8 molarity was used as an alkali activator. The variables in the study include alkaline to binder ratio and percentage of LECA to produce concrete of densities 1800 kg/m 3 and 2000 kg/m 3 . Fresh and harden characteristics of LWGPC are discussed in the form of slump and compressive strength respectively. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the First International con- ference on Advanced Lightweight Materials and Structures. 1. Introduction Generally, concrete having a density of 2200 kg/m 3 to 2600 kg/ m 3 . The concrete has a disadvantage that it has a relatively low strength to weight ratio. It is very important to consider the self- weight of the structure. Lightweight concrete can solve this prob- lem in structural applications. LWC is creating great interest in the research and increasing applications in construction technol- ogy [1]. The concrete having an oven-dry density of 2000 kg/m 3 is termed as lightweight concrete [2]. Lightweight concrete can be produced in three different methods those are foam concrete, lightweight aggregate concrete, and no fine concrete. Foam concrete can be produced by incorporating air bubbles into the cement paste or mortar [3]. No fine concrete has a unique property that eliminates the fine aggregate to convert normal con- crete into lightweight concrete. Due to the absence of fine aggre- gate in the no fine concrete cement holds the coarse aggregates in the mix and large volume of voids will be present in the concrete [4]. Lightweight aggregate concrete (LWAC) is produced using low density aggregates in the concrete mix. Aggregates having bulk density less than 1200 kg/m 3 are comes under lightweight aggre- gates [5]. The aggregates used in the concrete may include normal aggregates with combination of lightweight coarse aggregates and fine aggregates [1]. In case LWAC pores will not present in the mix, total mix will bind tightly as conventional concrete and low den- sity is due to voids present in the aggregate. Fig. 1 shows types of light weight aggregates briefly [6]. There are two types of aggre- gates natural and artificial LWA (Lightweight Aggregate). Natural materials are like volcanic tuffs, lava slag, riolite, perlite, LECA and vermiculite [7]. Artificial aggregates are flyash pebbles, expanded glass, LECA [8]. LECA are expanded clay aggregates man- ufactured in a rotary kiln which consists of a long, large-diameter steel cylinder inclined at an angle of about so to the horizontal. The kiln is lined internally in the firing zone with refractory bricks which, as the kiln rotates, become heated to the required temper- ature and ’roast’ the clay pellets for the required degree of expan- sion to occur. The length and configuration of the kiln depends in part on the composition of the clay and length of time it takes to ’condition’ the clay pellet in the pre-heater to reach a temperature of about 650 °C to avoid it shattering before becoming pyroplastic [5]. To utilize the flyash in the concrete Geopolymer concrete was adopted for the study. To activate the fly ash alkaline solutions https://doi.org/10.1016/j.matpr.2020.01.271 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the First International conference on Advanced Lightweight Materials and Structures. ⇑ Corresponding author. E-mail address: mukkala.priyanka@gmail.com (M. Priyanka). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: M. Priyanka, M. Karthikeyan and M. Sri Rama Chand, Development of mix proportions of geopolymer lightweight aggregate con- crete with LECA, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.271