Workability Of Geopolymer Concrete Research Articles

Workability and durability analysis of waste based geopolymer concrete

GPC as a promising material, started gaining momentous attention from the researchers and construction specialists because of its advantages in using by-products from agriculture and industries to replace cement thereby reducing greenhouse gas emission. Workability and durability tests were carried out, so as ascertain the efficiency of the rice husk ash and rice husk as sodium silicate and super plasticizer, for solving efflorescence problem known with geopolymer concrete. The factory-made sodium silicate was also used and compared with laboratory-produced, before addition of other geopolymer binders such as kaolin clay and fly ash. Brunauer-Emmett-Teller (BET) scrutiny that delivers quantitative data on the specific surface area as well as porosity dispersal of solid materials revealed that correlation coefficient of RHA (0.994) was higher than that of cement (0.991). Besides, RHA has higher surface area (250.023 m3/g) than the cement utilized which stood at 211.49 m3/g. Though the c constant of cement exceeds the RHA values, RHA can serve as good pozzolanic material and cement substitute. It is seen that the workability of laboratory-produced sodium silicate and superplasticizer geopolymer concrete was enhanced significantly compared to that of prior geopolymer systems. It is observed that the workability of the geopolymer concrete was considerably enhanced compared to that of orthodox geopolymeric systems, especially at 2.5% rice-husk created superplasticizer and higher content of laboratory-produced sodium silicate.

The Effect of Superplasticizer (SP) on the Workability and Skid Resistance of Geopolymer Concrete (GPC) Containing High Calcium Precursor (HCP)

A superplasticizer (SP) is one of the admixtures that may be used to improve the workability of concrete. However, its effects on geopolymer concrete (GPC) have yet to be well known or published, especially regarding its skid resistance and workability performance. This research aims to study the impact of the superplasticizer on the skid resistance and workability of geopolymer concrete containing high calcium precursor (HCP) in different proportions of SP, which are 0, 0.5, 1.0, 1.5 and 2.0 % by the weight of the HCP. Seven mix designs were produced: 1 conventional concrete mix, 5 geopolymers concrete mix, and 1 bituminous cold-mix asphalt mix. Slump flow and skid resistance tests were performed in this study. A skid resistance test is achieved using a British Pendulum Tester (BPT) on a 220 mm x 220 mm x 50 mm rectangle. This study found that the effect of SP on skid resistance is insignificant. However, the skid resistance of all GPC mix designs is higher than CC and asphalt mix. The workable flow of geopolymer concrete containing HCP and 0 - 2 % SP was 118-123 mm. However, less than 2 % of SP is given an insignificant difference. The optimum mix design of GPC is mix design GPC with an added 2 % SP (M6) that gives a high workability compared to other GPC mix designs and good skid resistance of 95 BPN. This study also found that workability correlates with skid resistance. The higher the spreading width value, the smaller the skid resistance value. In other words, the higher the flowability value, the less rough the sample surface. Hypothetically, the higher the percentage of SP, the higher the workability and the lower the skid resistance.

Effect of ambient curing periods on the mechanical properties of geopolymer concrete prepared with three mineral admixtures and glass fibers

Fly ash serves as the primary binder in geopolymer concrete (GPC), Several experiments have been performed using ground blast furnace slag (GGBS) as a fly ash additive in GPC and the results show that GGBS enrichment improves the mechanical properties. Existing experimental investigation employs a constant (optimum) percentage of condensed silica fume (CSF) along with GGBS as part replacement of fly ash in GPC of M40 grade. Glass fiber reinforcement was incorporated at percentages of 0.5,0.75 and 1.0 in the GPC composite. Laboratory specimens were prepared, and the mechanical properties were found at various curing periods ranging from 7 days to 60 days under ambient conditions. It is inferred that extended curing periods at ambient conditions have increased the mechanical strengths of GPC mixes. Glass fiber has contributed to strength increase, particularly in tension and flexure. Condensed silica fume has contributed towards more strength and workability of GPC.

The influence of low alkaline activator on the compressive strength and workability of geopolymer concrete

This paper presents the results of research on geopolymer concrete using a reasonably low alkaline activator. The key objective concerning this research is to investigate whether a low alkaline activator is still qualified to produce a concrete compressive strength that fulfills the structural requirements. The experimental program is carried out by making geopolymer concrete specimens, where the variables reviewed represented the amount of alkaline activator (4% and 5%), the ratio of alkaline activator to fly ash (AAS/FA) was 0.35, 0.4, 0.5, 0.6. The treatment temperatures of the specimens were room temperature (33°C) and 60°C. The experimental results of the compressive strength test have shown that the compressive strength of low alkaline geopolymer activator concrete still meets the requirements as a structural material (i.e. Indonesian Concrete Code). The weight of the resulting specimen is included in the category of normal weight concrete. The workability of geopolymer concrete with low alkaline activator tends to be better if the ratio AAS/FA also increases, but the compressive strength of concrete tends to decrease.

Variasi Molaritas Naoh Dan Alkali Aktivator Beton Geopolimer

Cement as a building material for concrete produces CO2 which can damage the earth's atmosphere. Therefore, environmentally friendly geopolymer concrete is the choice. The main ingredients for making this concrete are pozzolanic materials which are rich in Silica (SiO3) and Alumina (Al2O3) as a substitute for cement and alkali activator in the form of Sodium Hydroxide (NaOH) and (Na2SiO3) as binders.This study aims to determine the variation of the mixture for the highest compressive strength. The ratio of fly ash type F and alkali activator is 74%:26%. The molarity of NaOH used was 10M, 12M, 14M, the ratio of Na2SiO3 and NaOH was 2.5:1; 3.0:1; 3.5:1. The test object is cylindrical size 15cm x 30cm and the compressive strength test is 28 days old.The test results with the ratio of NaOH and Na2SiO3 2.5:1 at 10M, 12M, 14M NaOH are 25.81 Mpa, 27.00 MPa, 28.98 MPa. While the compressive characteristics are 24.32 Mpa, 24.67 Mpa, 26.58 Mpa. The test results show that the ratio of molarity and alkali activator greatly affects the compressive strength and workability of geopolymer concrete. High molarity will produce high compressive strength. Meanwhile, the higher the alkali activator ratio, the lower the compressive strength produced.Â

Phase change materials incorporated into geopolymer concrete for enhancing energy efficiency and sustainability of buildings: A review

To reduce CO2 emissions by 55% by 2030, applying sustainable and energy-efficient materials like geopolymer concrete containing Phase change materials (PCMs) for infrastructure development is necessary. This study reviews the geopolymer mortar and concrete containing PCMs, including their characterizations such as workability, density, compressive strength, heat capacity, thermal conductivity, and their effect on energy consumption in buildings. Existing literature reveals that using geopolymers instead of OPC can reduce thermal conductivity and power consumption. The latent heat and melting temperature of investigated PCMs were in the range of 96.1–230 J/g and 21.9–33.8 °C, respectively. Although microencapsulated PCMs (MPCMs) such as E-EVA and St-DVB have slightly reduced the compressive strength of geopolymers, they still show a high strength compared to typical strength classes in normal concrete. Also, the workability of geopolymer concrete can remain in the acceptable ranges when the PCMs are incorporated in the low percentages. Furthermore, a considerable increase in the heat capacity is reported at the PCM’s melting temperature of geopolymer mortars and concretes, which can be deployed to conserve energy in the buildings.

Mechanical and durability performance evaluation of heat cured low calcium fly ash based sustainable geopolymer concrete

An ever increasing demand for infrastructure growth all across the world is compelling the construction sector towards high amount of cement consumption. Cement production not only consumes large quantity of natural resources but also causes environment pollution by releasing tons of greenhouse gas into the atmosphere. Besides, huge extraction of sand from river beds is causing an ecological imbalance in the aquatic environment. In this context, this study aims towards the sustainable practice and investigated the fresh and hardened properties of sustainable geopolymer concrete by completely replacing the river sand with manufactured sand. The fresh and hardened properties that include workability, compressive strength, sulphate attack resistance and acid attack resistance were studied for samples cured at various temperatures. Additionally, surface deterioration, loss in weight and loss in compressive strength post exposure condition were considered for appraising the durability performance of geopolymer concrete. Workability of geopolymer concrete was enhanced by adding superplasticizer. The results revealed that higher compressive strength was achieved by heat curing the specimens at a temperature of 60 °C and geopolymer concrete exhibited superior resistance to sulphate attack and acid attack. Moreover, geopolymer concrete is proven to be cost effective and reduces the carbon emission.

Mix Design Proposed for Geopolymer Concrete Mixtures Based on Ground Granulated Blast furnace slag

ABSTRACT Nowadays, geopolymer concrete (GPC) usage is considered as a necessity for minimization the threats of environment through the reduction of cement consumption. Thus, a stepwise mix design methodology for GPC based on ground granulated blast furnace slag (GGBFS) was developed taking into consideration accomplishing convenient workability and compressive strength with feasible cost through using different variables. Besides, providing design charts at various curing circumstances. The mix design methodology was illustrated in a flow chart form which was clarified with the aid of an example. The experiments were conducted to investigate the impact of the setting time for geopolymer paste, workability and compressive strength for geopolymer concrete. The experimental outcomes demonstrate that an increment in compressive strength and workability of GPC was recognized due to the increment of slag content simultaneously an increment in the GPC compressive strength was observed with the increment in the curing temperature. While, the GPC mechanical properties increases through increasing sodium silicate solution to sodium hydroxide till R=3. However, the increase of sodium hydroxide molarity decreases the initial and setting time. Also, an increment in compressive strength was observed as superplasticizer ratio increases till 2.5% due to reduction in water demand and increment in reaction rate.

Study of Proportional Variation of Geopolymer Concrete which Self Compacting Concrete

Portland cement production process which is the conventional concrete constituent materials always has an impact on producing carbon dioxide (CO2) which will damage the environment. To maintain the continuity of development, while maintaining the environment, Portland cement substitution can be made with more environmentally friendly materials, namely fly ash. The substitution of fly ash material in concrete is known as geopolymer concrete. Fly ash is one of the industrial waste materials that can be used as geopolymer material. Fly ash is mineral residue in fine grains produced from coal combustion which is mashed at power plant power plant [15]. Many cement factories have used fly ash as mixture in cement, namely Portland Pozzolan Cement. Because fly ash contains SiO2, Al2O3, P2O3, and Fe2O3 which are quite high, so fly ash is considered capable of replacing cement completely.This study aims to obtain geopolymer concrete which has the best workability so that it is easy to work on (Workable Geopolymer Concrete / Self Compacting Geopolymer Concrete) and obtain the basic characteristics of geopolymer concrete material in the form of good workability and compressive strength. In this study, geopolymer concrete is composed of coarse aggregate, fine aggregate, fly ash type F, and activators in the form of NaOH and Na2SiO3 Be52. In making geopolymer concrete, additional ingredients such as superplastizer are added to increase the workability of geopolymer concrete. From this research, the results of concrete compressive strength above fc' 25 MPa and horizontal slump values reached 60 to 80 centimeters.

Rice-husk-based superplasticizer to increase performance of fly ash geopolymer concrete

Workability is a major drawback of fly-ash-based geopolymers due to high viscosity. In this research, a new type of superplasticizer is developed to overcome this workability issue. Due to the high viscosity of geopolymeric binder structures, none of conventional superplasticizers was found effective in maintaining the viscosity of the mixture. The novel hybrid superplasticizer was developed by utilizing agrowaste – that is, rice husk – and an alkaline activator. Characterization studies [by X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscope] of the material indicated that the amorphous silica from rice husk reacts with the alkaline activator – that is, sodium hydroxide – and results in the in situ synthesis of sodium silicate and lignin. The developed superplasticizer was used in different percentages in fly-ash-based geopolymeric systems to study its engineering properties. The workability of the fresh geopolymer concrete was measured using the slump cone test method as per IS 1199-1959, while the compressive strength was evaluated as per IS 516-1959, and it is reported that the workability of the geopolymer concrete was improved significantly compared to that of conventional geopolymeric systems. In the present work, an attempt has also been made to establish a working mechanism for the developed superplasticizer with geopolymeric systems, which indicated its compatibility with [–Si–O–Al–O–] n networks.

A quantitative method of approach in designing the mix proportions of fly ash and GGBS-based geopolymer concrete

This paper presents a systematic approach for selecting mix proportions for fly ash and GGBS-based geopolymer concrete. Very little information is available on complete methodology in designing the fly ash and GGBS-based geopolymer mix. The fly ash and GGBS were activated using sodium silicate and sodium hydroxide as alkaline activator solution. The Na2SiO3/NaOH (alkaline activator) ratio was taken as 2.5 and the concentration of NaOH solution was maintained at 8 M. The main parameters considered in this study were binder content and alkaline solution/binder ratio for various combinations of fly ash and GGBS. The variables considered in this experimentation include: binder content (360, 420 and 450 kg/m3), proportions of fly ash and GGBS (70–30, 60–40 and 50–50), alkaline solution/binder ratios (0.45, 0.50, 0.55 and 0.60) and curing condition (outdoor curing and oven curing). Results concluded that the GGBS content, alkaline solution/binder ratio and curing condition are found to be most influential parameters on compressive strength and workability of geopolymer concrete. The paper presents detailed examples of mix designs for various strengths.

Improving compressive strength of low calcium fly ash geopolymer concrete with alccofine

Geopolymer concrete is environmentally friendly and could be considered as a construction material to promote the sustainable development. In this paper fly ash based geopolymer concretes with different percentages of alccofine were made by mixing sodium hydroxide and sodium silicate as an alkaline activator and cured at ambient as well as heat environment in an electric oven at 90oC. Effects of various parameters such as the percentage of alccofine, curing temperature, a period of curing, fly ash content, was studied on compressive strength as well as workability of geopolymer concrete. The study concludes that the presence of alccofine improves the properties of geopolymer concrete during a fresh and hardened state of concrete. Geopolymer concrete in the presence of alccofine can be used for the general purpose of concrete as required compressive strength can be achieved even at ambient temperature. The 28 days compressive strength of 73 MPa, when cured at 90-degree Celsius, confirmed that it is also very suitable for precast concrete components.