scholarly journals Metakaolin Influence on Concrete Durability Properties

2019 ◽  
Vol 8 (11) ◽  
pp. 1109-1111
Keyword(s):  
Water Absorption ◽  
Mineral Admixture ◽  
Engineering Properties ◽  
Mineral Admixtures ◽  
Concrete Durability ◽  
Acid Attack ◽  
Initial Water ◽  
Durability Properties ◽  
Weight Losses ◽  
Permanence Properties

Mineral admixtures are being used today almost in all concretes partially, to improve workability, engineering properties and also to enhance durability of the concrete. These admixtures are industrial by-products. In the present study, mineral admixture such as metakaolin (MK) is replaced partially in cement to investigate permanence properties of concrete in terms of initial water absorption, final water absorption and confrontation to acid attack. Inorder to identify the durability properties, concrete of M30 grade was prepared. The mineral admixture content was varied from 0% to 30% by volume of cement with 10% gradient. In acid attack, 3% H2SO4 solution is used for curing of specimens and the corresponding weight losses (%) were evaluated for curing periods of 7 days, 14 days and 28 days. Both initial and final water absorptions of the metakaolin-modified concrete have been improved when metakaolin content was increased up to 10% advantageously. And, also weight loss was decreased when metakaolin content varied from 0% to 30%.

scholarly journals Durability Properties of Blast Furnace Slag (BFS)-Modified Concrete

2019 ◽  
Vol 8 (11) ◽  
pp. 831-833
Keyword(s):  
Blast Furnace ◽  
Water Absorption ◽  
Blast Furnace Slag ◽  
Engineering Properties ◽  
Mineral Admixtures ◽  
Acid Attack ◽  
Initial Water ◽  
Durability Properties ◽  
Weight Losses ◽  
Furnace Slag

Mineral admixtures are being used today almost in all concretes partially, to improve workability, engineering properties and also to enhance durability of the concrete. These are industries by-products. This paper discusses, blast furnace slag (BFS) was used to study durability properties; namely, initial water absorption, final water absorption and acid attack. To examine the above mentioned properties, M30 concrete was chosen. The BFS content was varied from 0% to 30% by volume of cement with an interval of 10%. In acid attack, specimens were cured in H2SO4 solution about 3% concentration, the corresponding weight losses (%) were evaluated for curing periods of 7, 14 and 28 days. The durability properties of the BFS-modified concrete have been improved when BFS content increased up to 20% advantageously. Weight loss was also decreased.

scholarly journals Fresh, Strength and Durability Characteristics of Binary and Ternary Blended Self Compacting Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 3987-3991
Keyword(s):  
Heat Of Hydration ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Strength Gain ◽  
Self Compacting Concrete ◽  
Supplementary Cementitious Material ◽  
Durability Properties ◽  
Granulated Blast Furnace Slag ◽  
Strength And Durability ◽  
Furnace Slag

Paper Mineral admixtures being the economical alternatives to Ordinary Portland Cement (OPC) for various normal and special concretes induce desirable properties to concrete such as higher flow, low heat of hydration, higher strength gain and enhanced durability. Ground granulated blast furnace slag(GGBFS) being one of the largely used mineral admixture alongside Fly Ash as supplementary cementitious material in concrete contributes to enhanced durability properties and low heat of hydration. Various replacement percentages of GGBS at 30%, 40%, 50% and 60% are used in binary blended Self compacting concrete(SCC) in the present study. At 40% replacement level, SCC exhibited improved workability, strength and durability properties. Alccofine(Ultrafine GGBS) used in ternary blended SCC enhanced early strength gain without affecting workability of SCC to a significant extent.

scholarly journals Water Absorption, Sorptivity and Permeability Properties of Concrete Containing Chemical and Mineral Admixtures

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
O.O. Akinkurolere
Keyword(s):  
Water Absorption ◽  
Permeability Coefficient ◽  
Mineral Admixtures ◽  
Concrete Durability ◽  
Permeability Test ◽  
Calcined Clay ◽  
Chemical Admixtures ◽  
Concrete Mix ◽  
The Right ◽  
Reduced Water

Concrete durability, especially in water-logged environments might not be possible with conventional constituents of concrete. A combination of mineral and chemical admixtures in different proportions is used to study water absorption, sorptivity, and permeability behavior of concrete. The water absorption, sorptivity, and permeability test were carried out using nine (9) trial mixes of different proportions of Calcined Clay (CC), Sawdust Ash (SDA), Crystalline Based Admixture (CBA), and Superplasticizer (SP). The results showed that treating concrete with 5% CC + 5% SDA+1% CBA combination gives optimum performance in terms of sorptivity with reduced water absorption value of 4.60%. While the permeability coefficient of concrete is reduced when CC and SDA are added to concrete mix separately, the reactivity between their combination (CC and SDA) significantly increased permeability coefficient of the concrete. The study demonstrates that production of concrete with the right proportions of admixture and pozzolanas improve the durability of concrete structures.

scholarly journals Durability Performance of Self-Compacting Concrete Containing Crumb Rubber, Fly Ash and Calcium Carbide Waste

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 488
Author(s):  
Sylvia Kelechi ◽  
Musa Adamu ◽  
Abubakar Mohammed ◽  
Yasser Ibrahim ◽  
Ifeyinwa Obianyo
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Calcium Carbide ◽  
Crumb Rubber ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Acid Attack ◽  
Self Compacting Concrete ◽  
Durability Properties

Waste tire disposal continues to pose a threat to the environment due to its non-biodegradable nature. Therefore, some means of managing waste tires include grinding them to crumb rubber (CR) sizes and using them as a partial replacement to fine aggregate in concrete. However, the use of CR has a series of advantages, but its major disadvantage is strength reduction. This leads to the utilization of calcium carbide waste (CCW) to mitigate the negative effect of CR in self-compacting concrete (SCC). This study investigates the durability properties of SCC containing CR modified using fly ash and CCW. The durability properties considered are water absorption, acid attack, salt resistance, and elevated temperature of the mixes. The experiment was conducted for mixes with no-fly ash content and their replica mixes containing fly ash to replace 40% of the cement. In the mixes, CR was used to partially replace fine aggregate in proportions of 0%, 10%, and 20% by volume, and CCW was used as a partial replacement to cement at 0%, 5%, and 10% by volume. The results indicate that the mixes containing fly ash had higher resistance to acid (H2SO4) and salt (MgSO4), with up to 23% resistance observed when compared to the mix containing no fly ash. In addition, resistance to acid attack decreased with the increase in the replacement of fine aggregate with CR. The same principle applied to the salt attack scenario, although the rate was more rapid with the acid than the salt. The results obtained from heating indicate that the weight loss was reduced slightly with the increase in CCW, and was increased with the increase in CR and temperature. Similarly, the compressive strength was observed to slightly increase at room temperature (27 °C) and the greatest loss in compressive strength was observed between the temperature of 300 and 400 °C. However, highest water absorption, of 2.83%, was observed in the mix containing 20% CR, and 0% CCW, while the lowest water absorption, of 1.68%, was found in the mix with 0% CR, 40% fly ash, and 10% CCW. In conclusion, fly ash is recommended for concrete structures immersed in water, acid, or salt in sulphate- and magnesium-prone areas; conversely, fly ash and CR reduce the resistance of SCC to heat beyond 200 °C.

scholarly journals Research on Curing Water Demand of Cementing Material System Based on Hydration Characteristics

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7098
Author(s):  
Wang Yao ◽  
Baolin Guo ◽  
Zhenyu Yang ◽  
Xingxing Yang ◽  
Yongzhi Guo ◽  
...  
Keyword(s):  
Water Demand ◽  
Pure Water ◽  
Bound Water ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Concrete Durability ◽  
Material System ◽  
Early Hydration ◽  
Cover Concrete ◽  
Cementing Material

The performance of cover concrete is acknowledged as a major factor governing the degradation of concrete structures. Curing plays a vital role in the development of concrete durability. The effects of different water-binder ratios and mineral admixtures on the curing water demand of concrete were studied by the surface water absorption test. Combined with the characteristics of the hydration heat and chemically bound water of the composition cementing material system, the law of variation for curing water demand was analyzed. The results show that the addition of mineral admixtures can reduce the early hydration rate and hydration exothermic characteristics, and the hydration degree decreases with the increase of mineral admixtures. Due to the filling effect and active effect, the addition of fly ash (FA) and ground granulated blast slag (GGBS) reduces the curing water demand. The curing water demand of cover concrete decreases with the increase of mineral admixture content, and the curing water demand of pure water is the maximum and that of mix FA and GGBS is the minimum. Moreover, there is a strong correlation between the cumulative curing water demand and the chemically bound water content, indicating that the power of water migration mainly comes from the hydration activity of the cementing material system. The results provide a theoretical basis for the fine control of a concrete curing system.

scholarly journals NaOH Molarity's Impacts on SCGC's Workability and Durability with Ecologically Friendly Industrial By-Products

2020 ◽  
Vol 9 (3) ◽  
pp. 2370-2378
Keyword(s):  
Fly Ash ◽  
Water Absorption ◽  
Sulphuric Acid ◽  
Experimental Result ◽  
Acid Attack ◽  
Durability Properties ◽  
Slump Flow ◽  
Binder Ratio ◽  
Strength And Durability ◽  
Sulphuric Acid Medium

The objective of the analysis is to investigate the workability and durability properties of self-compacting geopolymer concrete (SCGC) based on fly ash and GGBS on various NaOH molarities. A system of trial and error was employed to achieve the SCGC mix ratio. By conducting workability properties test such as slump flow, T50 slump flow, V-funnel, and L-box and At 28, 56 and 90 days, durability properties such as water absorption, sulphuric acid attack and sorptivity were tested. The specimens have been cured for 24 hours in the oven at 70 ° C, and environmental healing is accompanied by the test days respectively. For all the molarities including 8, 10 and 12 M with a constant binding content of 400 kg / m3, the fly ash mass fraction was changed by GGBS by 0, 30, 50, and 70 per cent by weight. In all molarities, the fluid to binder ratio of 0.47 by mass has been kept constant and the S.P dosage has remained consistent with 0% replacement and 4% with 30, 50 and 70% replacement and the water content has therefore changed accordingly. The experimental result showed lower workability parameters such as slump flow and L-box ratios with increased molarity and GGBS content, increased T50 slump flow and increased V-Funnel with increased molarity and GGBS content, and the whole study was performed as suggested by the EFNARC guidelines. Durability properties such as water absorption and sorptiveness have shown good resistance with an increase of the GGBS content and an increase in molarity. Seventy percent fly-ash replacement by GGBS showed more strength degradation when held at 5percent concentration in the sulphuric acid medium. Hence SCGC can be a better replacement for normal OPC concrete both in terms of strength and durability with reduced CO2 emission.

scholarly journals Effects of Different Types of Fibers on the Physical and Mechanical Properties of MICP-Treated Calcareous Sand

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 268
Author(s):  
Jitong Zhao ◽  
Huawei Tong ◽  
Yi Shan ◽  
Jie Yuan ◽  
Qiuwang Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Glass Fiber ◽  
Physical And Mechanical Properties ◽  
Polyester Fiber ◽  
Engineering Properties ◽  
Fiber Types ◽  
Calcite Precipitation ◽  
Calcareous Sand ◽  
Hemp Fiber

Microbial-induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties through the precipitation of calcium carbonate (CaCO3) on the contact and surface of soil particles in recent years. In the present experiment, water absorption and unconfined compressive strength (UCS) tests were carried out to investigate the effects of three different fiber types (glass fiber, polyester fiber, and hemp fiber) on the physical and mechanical properties of MICP-treated calcareous sand. The fibers used were at 0%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, and 0.40% relative to the weight of the sand. The results showed that the failure strain and ductility of the samples could be improved by adding fibers. Compared to biocemented sand (BS), the water absorption of these three fiber-reinforced biocemented sands were, respectively, decreased by 11.60%, 21.18%, and 7.29%. UCS was, respectively, increased by 24.20%, 60.76%, and 6.40%. Polyester fiber produced the best effect, followed by glass fiber and hemp fiber. The optimum contents of glass fiber and polyester fiber were 0.20% and 0.25%, respectively. The optimum content of hemp fiber was within the range of 0.20–0.25%. Light-emitting diode (LED) microscope and scanning electron microscope (SEM) images lead to the conclusion that only a little calcite precipitation had occurred around the hemp fiber, leading to a poor bonding effect compared to the glass and polyester fibers. It was therefore suggested that polyester fiber should be used to improve the properties of biocemented sand.

Effects of Fly Ash and Granular Blast-Furnace Slag on Development Rate of Strength of Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 371-375
Author(s):  
Ji Wei Cai ◽  
Si Jia Yan ◽  
Gong Lei Wei ◽  
Lu Wang ◽  
Jin Jin Zhou
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Development Rate ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Conventional Concrete ◽  
Enhancing Effect ◽  
Substitution Content ◽  
Furnace Slag

Fly ash (FA) and granular blast-furnace slag (GBFS) are usual mineral admixtures to conventional concrete, and their contents substituted for Portland cement definitely affect development rate of strength of concrete. C30 and C60 concrete samples with FA and/or GBFS were prepared to study the influence of substitution content of the mineral admixtures on 3 d, 7 d and 28 d strength. The results reveal that the development rate of strength in period from 3 d to 7 d gets slow with increasing content of mineral admixtures except for concrete with only GBFS less than 20%. In the case of substituting FA as the only mineral admixture for part of cement, the development rate of strength of C30 concrete in period from 7 d to 28 d keeps roughly constant even that of C60 concrete increases. When substituting mineral admixtures in the presence of GBFS for cement within experimental range, the development rate of strength in period from 7 d to 28 d gets fast with increasing substitution content. The enhancing effect of combining FA and GBFS occurs in period from 7 d to 28 d for both C30 and C60 concretes (FA+GBFS≤40%), even occurs in period from 3 d to 7 d for C60 concrete. Based on 7 d strength and the development rate, 28 d strength of concrete can be predicted accurately.

Permeability of Lightweight Aggregate Concrete with Mineral Admixture

2013 ◽  
Vol 857 ◽  
pp. 105-109
Author(s):  
Xiu Hua Zheng ◽  
Shu Jie Song ◽  
Yong Quan Zhang
Keyword(s):  
Pore Structure ◽  
Lightweight Concrete ◽  
Chloride Ion ◽  
Lightweight Aggregate ◽  
Total Porosity ◽  
Normal Weight ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete

This paper presents an experimental study on the permeability and the pore structure of lightweight concrete with fly ash, zeolite powder, or silica fume, in comparison to that of normal weight aggregate concrete. The results showed that the mineral admixtures can improve the anti-permeability performance of lightweight aggregate concrete, and mixed with compound mineral admixtures further more. The resistance to chloride-ion permeability of light weight concrete was higher than that of At the same strength grade, the anti-permeability performance of lightweight aggregate concrete is better than that of normal weight aggregate concrete. The anti-permeability performance of LC40 was similar to that of C60. Mineral admixtures can obviously improve the pore structure of lightweight aggregate concrete, the total porosity reduced while the pore size decreased.

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