scholarly journals Sulfuric acid corrosion of geopolymer concrete with mineral additives from wastes

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Nadezhda Eroshkina ◽  
Mikhail Chamurliev ◽  
Mark Korovkin
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Portland Cement ◽  
Geopolymer Concrete ◽  
Acid Solutions ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Demolition Waste ◽  
Sulfuric Acid Solutions ◽  
Mineral Additives

The effect of mineral additives such as crushed ash and individual building demolition waste on the corrosion resistance of geopolymer concrete based on screening the crushed granite and blast furnace slag in an environment of sulfuric acid solutions was studied. The corrosion resistance of concrete was evaluated by the kinetics of reducing the mass and strength of samples in sulfuric acid solutions with a concentration of 2,5 and 5 % for 10 days. It was shown that replacing 50 % of granite powder with ground crushed bricks or ash significantly increases the corrosion resistance of geopolymer materials. It was established that due to the formation of poorly soluble products of the interaction of sulfuric acid and concrete in the pores of a geopolymer stone, an interface is formed between the undestructed material and the zone subjected to destructive processes, which impedes the penetration of the corrosive medium into the material. The study also conducted comparative studies of the corrosion resistance of Portland cement concrete with various water-cement ratios. The research results showed that under the influence of sulfuric acid in Portland cement concrete this border does not form and a rapid loss of mass and strength occurs in the samples. The established feature of the process of destruction of geopolymer concrete in a solution of sulfuric acid is the reason for its higher resistance in comparison with cement concrete.

Acid Attack Resistance of Magnesium Phosphate Cement

2016 ◽  
Vol 680 ◽  
pp. 392-397
Author(s):  
Zhu Ding ◽  
Meng Xi Dai ◽  
Can Lu ◽  
Ming Jie Zhang ◽  
Peng Cui
Keyword(s):  
Compressive Strength ◽  
Acid Solution ◽  
Portland Cement ◽  
Magnesium Phosphate ◽  
Acid Solutions ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Acid Attack ◽  
High Acid ◽  
Repair Materials

Magnesium phosphate cements (MPC) had been used as repair materials for deteriorated Portland cement concrete structures. In this paper a new MPC was prepared and the basic properties including workability and compressive strength were tested. The acid attack resistance of MPC was investigated by immersing the MPC mortars in solutions at pH 3, 5, and 7, for 14d, 28d and 60d respectively. The compressive strength of MPC mortars after acid attack was tested and the microstructure of MPC were examined. The results showed that the compressive strength of MPC decreased after immersion in acid solution for 14d and 28d, however the strength of MPC with suitable materials mixture can recovered again after 60d immersion. The results indicated MPC has high acid attack resistance in static acid solution. The behavior of MPC in flowing acid solutions is need to be studied further.

Seawater Corrosion Resistance of Low Heat Portland Cement Concrete

2015 ◽  
Vol 814 ◽  
pp. 207-213
Author(s):  
Ning Wang ◽  
Xiao Wei Cheng ◽  
Yun Xia Yang
Keyword(s):  
Corrosion Resistance ◽  
Portland Cement ◽  
Test Specimen ◽  
Sem Analysis ◽  
Corrosion Mechanism ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Quality Change ◽  
Seawater Corrosion ◽  
Drying Test

With the analysis of the seawater corrosion effect on low-heat Portland cement concrete under wetting-drying test, the compressive strength and quality change of concrete test specimen were investigated for different test periods. According to the evaluation of seawater corrosion resistance, the low-heat Portland cement showed better corrosion resistance than that of ordinary Portland cement and moderate-heat Portland cement. Moreover, the corrosion mechanism was expounded through XRD and SEM analysis. It was found that lots of C2S in the low-heat Portland cement play an important role in corrosion resistance of cement concrete.

scholarly journals Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ganesan Lavanya ◽  
Josephraj Jegan
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Sodium Hydroxide ◽  
Ordinary Portland Cement ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Ordinary Portland Cement Concrete

This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were150×150×150 mm cubes,100×200 mm cylinders, and100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

scholarly journals On effect of superplasticizers and mineral additives on shrinkage of hardened cement paste and concrete

2018 ◽  
Vol 196 ◽  
pp. 04018 ◽  
Author(s):  
Grigory Nesvetaev ◽  
Yulia Koryanova ◽  
Tatiana Zhilnikova
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Hardened Cement ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Hardened Cement Paste ◽  
Mineral Additive ◽  
Mineral Additives

A model describing the variation in autogenous shrinkage and drying shrinkage of portland cement concrete, depending on the volume of aggregates and the shrinkage of hardened cement paste, is presented. The equation to calculate shrinkage of concrete as a function of the volume of aggregates and shrinkage of a hardened cement paste was proposed. Formulas are proposed that describe the change in the shrinkage of hardened cement paste as a function of water/cement. The results of studies of the effect of superplasticizers and mineral additives on the autogenous shrinkage and the drying shrinkage of hardened cement paste are presented. Concretes made with superplasticizer and mineral additive may have the potential lower the value of drying shrinkage. The shrinkage value can be lowered from 30% till 70%. Concretes containing superplasticizers and mineral additives can potentially have the autogenous shrinkage reduced to 75%, or increased to 180%.

scholarly journals Structural analysis of composite metakaolin-based geopolymer concrete

2018 ◽  
Vol 11 (3) ◽  
pp. 535-543 ◽  
Author(s):  
F. PELISSER ◽  
B. V. SILVA ◽  
M. H. MENGER ◽  
B. J. FRASSON ◽  
T. A. KELLER ◽  
...  
Keyword(s):  
Portland Cement ◽  
Concrete Beam ◽  
Rupture Strength ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Two Samples ◽  
Geopolymer Cements ◽  
Geopolymer Cement ◽  
Nonlinear Numerical Model

Abstract The study of alternative binders to Portland cement, such as geopolymer cements, offers the chance to develop materials with different properties. With this purpose, this study evaluated experimentally the mechanical behavior of a geopolymer concrete beam and compared to a Finite Element (FE) nonlinear numerical model. Two concrete beams were fabricated, one of Portland cement and another of metakaolin-based geopolymer cement. The beams were instrumented with linear variable differential transformers and strain gauges to measure the deformation of the concrete and steel. Values for the compressive strength of the geopolymer cement concrete was 8% higher than the Portland cement concrete (55 MPa and 51 MPa, respectively) and the tensile rupture strength was also 8% higher (131 kN) for the geopolymer concrete beam in relation to Portland cement concrete beam (121 kN). Distinct failure mechanisms were verified between the two samples, with an extended plastic deformation of the geopolymer concrete, revealing post-fracture toughness. The geopolymer concrete showed higher tensile strength and better adhesion in cement-steel interface.

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