Production of aerated alkali-activated slag pastes and mortars using hydrogen peroxide

Download
2017
Şahin, Murat
Utilization of ground granulated blast furnace slag (GGBFS) through alkali activation for the production of construction materials can provide economic and environmental advantages. In this study, cement-free lightweight composites based on the alkali activation of GGBFS were produced with the incorporation of hydrogen peroxide, and their physical, thermal, and mechanical properties were investigated, under different curing conditions. Various water-to-slag ratios (W/S), hydrogen peroxide contents, and sand-to-slag ratios (Sa/S) were used to explore the expansion mechanism of fresh mixtures and to investigate the apparent density of produced samples. The compressive and flexural strengths and water absorption of sealed-cured pastes and mortars were investigated at room temperature. In addition, the effect of ambient curing and humid-oven curing on the compressive strengths of selected series of pastes and mortars were investigated. Thermal conductivities of aerated pastes were measured. The size and amount of pores were assessed on selected series of aerated pastes and mortars. Aerated pastes and mortars were produced in the apparent density range of 516-1603 kg/m3 and with 0.5-30.0 MPa compressive strength. Thermal conductivities of aerated pastes varied from 0.117-0.206 W/m.K in the dry density range of 480-1098 kg/m3. The use of hydrogen peroxide in the range of 0.25 %-0.75 % (by mass of slag) was sufficient to produce lightweight composites which can be used for insulation and semi-structural purposes in the construction industry.

Suggestions

Effect of alkali-silica reaction expansion on mechanical properties of concrete
Hafçı, Alkan; Turanlı, Lütfullah; Department of Civil Engineering (2013)
Alkali-silica reaction (ASR) is a chemical deterioration process which arises in concrete due to reactive aggregate from its constituent, sufficient alkalis from cement or external resources and humidity about 85%. ASR gel, formed by the reaction, absorbs water and expands so that it causes expansion and cracking in concrete. ASR has detrimental effects on mechanical properties of concrete. Therefore, ASR which is a long and a constantly progressive reaction may become a threat to the safety of concrete str...
Coupled thermomechanical analysis of concrete hardening
Andiç, Halil İbrahim; Göktepe, Serdar; Yaman, İsmail Özgür; Department of Civil Engineering (2015)
Thermomechanically coupled modeling of fresh concrete allows us to predict the interaction between thermal and mechanical mechanisms throughout the setting and hardening process. Because of cement hydration, an excessive temperature increase may occur in the interior regions of mass concrete structures. This temperature increase along with the thermal boundary conditions may result in thermal gradients within concrete structures. Owing to the thermal gradients and mechanical constraints, thermally induced s...
Comparative evaluation of steel mesh, steel fiber and high performance polypropylene fiber-reinforced concrete in panel/beam tests
Ceylan, Semih; Turanlı, Lütfullah; Department of Civil Engineering (2014)
Comparison of concrete mixtures containing steel mesh, steel fiber and polypropylene fibers were evaluated in terms of toughness, flexural strength, compressive strength and split tensile strength. Five types of concrete were prepared with steel mesh, steel fiber and polypropylene fiber with the identical water/cement (w/c) ratio and the identical workability. 10x60x60 cm plates, 8x8x32 cm beams and 10x20 cm cylindrical concrete specimens were prepared. Compressive strength, split-tensile strength and tough...
Effect of ground perlite incorporation on the performance of blended cements
Erdem, T. K.; Akgül, Çağla; Tokyay, Mustafa; Erdoğan, Turhan Y. (2007-06-13)
Perlite is a volcanic rock that contains relatively high amounts of SiO2 and Al2O3. Due to its proper chemical composition and glassy structure, it can be used as a pozzolanic addition in blended cements. In this study, ground perlite was used as a cement replacement material in blended cements. Several mortar mixes were prepared to investigate the performance of those cements. The results showed that perlite incorporation caused early age strength losses when compared to the control mortars containing only...
Effect of Synthetic Fibers on Energy Absorption Capacity of Normal and High Performance Concrete
Şengün, Emin; Alam, Burhan; Yaman, İsmail Özgür (null; 2016-06-08)
With the increasing aim of incorporating concrete in different applications and infrastructure elements, the use of macro synthetic fiber incorporated concretes has become real popular thanks to their high energy absorption capacity, toughness and impact resistance. The aim of this study is to investigate the effects of synthetic fibers on toughness and energy absorption of normal and high performance concretes. For this experimental study, eight concrete groups were designed using synthetic fibers of vario...
Citation Formats
M. Şahin, “Production of aerated alkali-activated slag pastes and mortars using hydrogen peroxide,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.