scholarly journals Development of Self-Cured Sustainable Concrete Using Local Water-Entrainment Aggregates of Vesicular Basalt

2021 ◽  
Vol 13 (12) ◽  
pp. 6756
Author(s):  
Mohd. Ahmed ◽  
Saeed AlQadhi ◽  
Saleh Alsulamy ◽  
Saiful Islam ◽  
Roohul A. Khan ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Surface Area ◽  
Water Permeability ◽  
Concrete Strength ◽  
The Self ◽  
Bet Surface Area ◽  
Hardened Concrete ◽  
Sustainable Concrete ◽  
Vesicular Basalt ◽  
Water Entrainment

The environmental and economic concerns pertaining to the construction industry have necessitated the development of sustainable concrete. Durability and strength are the two primary properties which determine the sustainability of concrete. This study evaluated the performance of self-cured concrete produced from local vesicular basalt porous aggregates. The durability indicators, porosity, permeability and pore size of the hardened concrete, were obtained from the water sorptivity (water permeability under capillary action) test, the water permeability under pressure action test and the Brunauer–Emmett–Teller (BET) surface area test and strength was evaluated in terms of compressive strength of concrete. The concrete specimens were produced with 10% porous vesicular basalt aggregate in replacement of coarse aggregate. The concrete specimens were tested at 3, 7 and 28 days. The self-curing effect on concrete strength was evaluated against water, air and membrane cured specimens, at surface/volume ratio of 26.4/40 and w/c ratio of 0.35/0.5. A 20% decrease in sorptivity coefficient, 10% increase in solid surface area and about 10% increase in compressive strength of the self-cured concrete was observed over the conventionally cured concrete. The study concludes that the addition of water-entrainment aggregates to concrete reduces water permeability, results in a finer pore structure of concrete and increases the quality and durability of concrete.

scholarly journals Self-Healing of Concrete Cracks by Ceramsite-Loaded Microorganisms

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jing Xu ◽  
Xianzhi Wang ◽  
Junqing Zuo ◽  
Xiaoyan Liu
Keyword(s):  
Heat Treatment ◽  
Compressive Strength ◽  
Heating Temperature ◽  
Concrete Strength ◽  
The Self ◽  
Self Healing ◽  
Healing Efficiency ◽  
Maximum Crack ◽  
Harsh Conditions ◽  
Urea Decomposition

Protective carrier is essential for the self-healing of concrete cracks by microbially induced CaCO3 precipitation, owing to the harsh conditions in concrete. In this paper, porous ceramsite particles are used as microbial carrier. Heat treatment and NaOH soaking are first employed to improve the loading content of the ceramsite. The viability of bacterial spores is assessed by urea decomposition measurements. Then, the self-healing efficiency of concrete cracks by spores is evaluated by a series of tests including compressive strength regain, water uptake, and visual inspection of cracks. Results indicate that heat treatment can improve the loading content of ceramsite while not leading to a reduction of concrete strength by the ceramsite addition. The optimal heating temperature is 750°C. Ceramsite particles act as a shelter and protect spores from high-pH environment in concrete. When nutrients and spores are incorporated in ceramsite particles at the same time, nutrients are well accessible to the cells. The regain ratio of the compressive strength increases over 20%, and the water absorption ratio decreases about 30% compared with the control. The healing ratio of cracks reaches 86%, and the maximum crack width healed is near 0.3 mm.

scholarly journals Influence of Rice Husk Ash Density on the Workability and Strength of Structural Concrete

2017 ◽  
Vol 2 (3) ◽  
pp. 36 ◽  
Author(s):  
John Kamau ◽  
Ash Ahmed ◽  
Fraser Hyndman ◽  
Paul Hirst ◽  
Joseph Kangwa
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Water Demand ◽  
Rice Husk Ash ◽  
Concrete Strength ◽  
High Water ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hardened Concrete ◽  
Structural Applications

Supplementary cementitious materials (SCMs) have been known to improve the properties of fresh and hardened concrete, and at the same time enhance the sustainability of concrete. Rice husk Ash (RHA), is one such material, but has neither been widely studied nor applied in practice. This work investigated the effect of the density of RHA on the workability and compressive strength of fresh and hardened RHA-replaced concrete respectively. Cement was replaced with RHA in concrete by weight (RHA-W) and by volume (RHA-V) at steps of 0%, 5%, 7.5%, 10%, 15%, 20%, 25% and 30%. The 0% replacement was used as the reference point from which performances were measured. Results showed that unlike the characteristic of other established pozzolans, RHA significantly reduced the workability of wet concrete and the rate of compressive strength gain over curing time due to a high water demand that is caused by the increased volume of replaced concrete, which results from its low density. Workability reduced with increased replacement for both RHA-W and RHA-V. Replacements of above 15% were not possible for the RHA-W due to the high water demand. However, replacements of up to 30% were achieved for the RHA-V. RHA-W specimens achieved lower compressive strengths and were observed to gain strength at a lower rate over the 28 to 91-days period of curing compared to RHA-V specimens. This behavior was attributed to the shortage of water that is necessary for the hydration of cement and subsequent pozzolanic reaction, which is the basis of the contribution that is made to the strength and performance of concrete by SCMs. However, the compressive strengths achieved were above the study’s target concrete strength of class C32/40 at 91 days, which is among those classes that are listed as being durable and suitable for structural applications. A conclusion that RHA should supplement cements by volumetric replacement rather than simple substitution by weight was drawn.

scholarly journals EFFECT OF BET SURFACE AREA AND REPLACEMENT RATIO OF VOLCANIC GLASS POWDER ON COMPRESSIVE STRENGTH

2020 ◽  
Vol 73 (1) ◽  
pp. 465-470
Author(s):  
Atsushi TOMOYOSE ◽  
Takafumi NOGUCHI ◽  
Kenichi SODEYAMA ◽  
Kazuro HIGASHI
Keyword(s):  
Compressive Strength ◽  
Surface Area ◽  
Glass Powder ◽  
Volcanic Glass ◽  
Bet Surface Area ◽  
Replacement Ratio

scholarly journals THE EFFECT OF MICROENCAPSULATED PHASE-CHANGE MATERIAL ON THE COMPRESSIVE STRENGTH OF STRUCTURAL CONCRETE

2013 ◽  
Vol 8 (3) ◽  
pp. 116-124 ◽  
Author(s):  
Chad Norvell ◽  
David J. Sailor ◽  
Peter Dusicka
Keyword(s):  
Compressive Strength ◽  
Energy Storage ◽  
Phase Change ◽  
Building Materials ◽  
Energy Use ◽  
Phase Change Materials ◽  
Structural Integrity ◽  
Concrete Strength ◽  
Hardened Concrete ◽  
Filler Materials

Latent heat energy storage through phase-change materials (PCMs) is one possible strategy to control interior temperatures in buildings, improve thermal comfort, and passively reduce building energy use associated with heating and cooling. While PCMs integrated into building structure elements have been studied since the 1970s, challenges of integrating PCMs into building materials while maintaining their heat storage benefits have limited their application in practice. The recent introduction of microencapsulated phase-change materials provides the energy storage capability of PCMs in micron-scale, chemically-inert capsules that can be easily integrated into composite materials such as gypsum wallboard and concrete. The size and physical properties of microencapsulated PCMs suggest that they will behave similarly to filler materials in concrete. Such filler materials are generally less than 125 μm in diameter and can increase concrete strength when added to a mix. This study uses the compressive strength of hardened concrete mixes with varying amounts of PCM to evaluate the effect of PCM addition on concrete structural integrity.

scholarly journals The Effect of Crystalline Waterproofing Admixtures on the Self-Healing and Permeability of Concrete

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1860
Author(s):  
Anita Gojević ◽  
Vilma Ducman ◽  
Ivanka Netinger Grubeša ◽  
Ana Baričević ◽  
Ivana Banjad Pečur
Keyword(s):  
Compressive Strength ◽  
Penetration Depth ◽  
Initial Crack ◽  
The Self ◽  
Hardened Concrete ◽  
Self Healing ◽  
Crack Healing ◽  
Water Penetration ◽  
Binder Ratio ◽  
Water Binder Ratio

This paper investigates the effectiveness of a specific crystalline waterproofing admixture (CWA) in concrete as a function of a water–binder ratio. Four concrete mixes with and without CWA were prepared; two of them with a water–binder ratio of 0.45 and two of them with a water–binder ratio of 0.55. Water permeability and compressive strength were tested on hardened concrete specimens and self-healing of cracks over time was observed. Cement paste and CWA paste were prepared to clarify the results obtained on the concrete specimens. SEM and EDS and XRD and FTIR were performed on the hardened pastes to explain the mechanism of CWA working. The results show that the addition of CWA had no significant effect on the compressive strength of the concrete, but reduced the water penetration depth in the concrete, and the reduction was more effective for mixes with lower water–binder ratio. Regarding the self-healing effect, it can be concluded that the addition of CWA improves the crack healing in concrete, but the efficiency of self-healing is highly dependent on the initial crack width. The mechanisms involved in the reduction of water penetration depth and crack healing in concrete can be explained by different mechanisms; one is creation of the CSH gel from unreacted clinker grains, then formation carbonate, and additional mechanism is gel formation (highly expansive Mg-rich hydro-carbonate) from magnesium based additives. The presence of sodium silicate, which would transform into carbonate/bicarbonate, also cannot be excluded.

scholarly journals Efficiency of rice husk ash and fly ash as reactivity materials in sustainable concrete

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Mohamed Amin ◽  
Bassam Abdelsalam Abdelsalam
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Rice Husk ◽  
Water Permeability ◽  
Rice Husk Ash ◽  
Experimental Program ◽  
Hardened Concrete ◽  
Concrete Mixtures

AbstractMany environmental problems occur due to rice husk burning and emissions from coal-fired power stations. This paper presents the recycling of rice husk ash (RHA) and fly ash (FA) from power plants as reactivity materials for producing sustainable (green) concrete. This research aims to investigate the efficiency of RHA and FA replacement ratios on fresh and hardened properties of concrete mixtures. The experimental program consisted of 21 concrete mixtures, which were divided into three groups. The cementitious material contents were 350, 450 and 550 kg m−3 for groups one, two and three, respectively. The replacement ratios from the cement content were 10, 20 and 30% respectively, for each recycle material (RHA and FA). The slump and air contents of fresh concrete were measured. The compressive strength, splitting tensile strength, flexural strength, modulus of elasticity and bond strength of hardened concrete as mechanical properties were also analyzed. The compressive strength was monitored at different ages: 3, 7, 28, 60 and 90 d. The water permeability test of hardened concrete as physical properties was conducted. Test results showed that the RHA and FA enhanced the mechanical and physical properties compared with the control mixture. The cementitious content of 450 kg m−3 exhibited better results than other utilized contents. In particular, the replacement ratios of 10 and 30% of RHA presented higher mechanical properties than those of FA for each group. The water permeability decreased as the cementitious content increased due to the decrease in air content for all mixtures. The water permeability loss ratios increased as the cementitious content decreased.

scholarly journals Water Permeability Characteristics of Normal Strength Concrete Made from Crushed Clay Bricks as Coarse Aggregate

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Syed Ishtiaq Ahmad ◽  
Mohammad Anwar Hossain
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Water Permeability ◽  
Coarse Aggregate ◽  
Natural Stone ◽  
Hardened Concrete ◽  
Depth Of Penetration ◽  
Crushing Strength ◽  
Permeability Characteristics ◽  
Clay Bricks

Water permeability characteristic of concrete made from crushed clay bricks as coarse aggregate is investigated and compared with concrete made from natural stone aggregate. For this, six different brick and five different natural stone samples were selected. Crushing strength of brick samples and water absorption of aggregate produced from them were also measured. Concrete samples of three different compressive strengths were prepared as per ACI mix design method from each of these aggregate samples. Compressive strength of concrete that could be achieved with brick aggregate varied between 19 and 28 MPa, whereas, for stone aggregate, compressive strength varied between 24 and 46 MPa. These samples were then tested for water permeability using the AT 315 machine as per EN 12390-8: “Depth of Penetration of Water under Pressure.” Experimental results and subsequent analysis indicate that water permeability of brick aggregate concrete is 225% to 550% higher than that of concrete made from natural stone aggregate of identical compressive strength. Water permeability was found to be directly related to compressive strength, water absorption, and porosity of hardened concrete. It was also observed that water permeability of concrete is influenced by water absorption of brick aggregate and crushing strength of brick.

scholarly journals INFLUENCE OF VISCOSITY MODIFYING AGENT ON SOME RHEOLOGICAL PROPERTIES, SEGREGATION RESISTANCE AND COMPRESSIVE STRENGTH OF SELF-COMPACTING CONCRETE

2013 ◽  
Vol 19 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Anna M. Grabiec
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Concrete Strength ◽  
Vertical Direction ◽  
Reference Level ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Modifying Agent ◽  
Air Content ◽  
Concrete Mix

Rheological properties of self-compacting concrete mixes containing a viscosity modifying agent (VMA) in their composition were studied. After preliminary studies self-compacting concrete mixes and, particularly, a fluid concrete mix prone to segregation of its ingredients were chosen. VMA was added in various amounts to that concrete mix to check how it performed in fresh and hardened concrete. Main studies focused on the influence of VMA on the following properties of concrete mixes: the slump flow, the flow time into the diameter of 500 mm and the resistance to segregation in the vertical direction. Moreover, the air content of concrete mixes and the 28-day compressive strength of concrete were measured. Test results showed that VMA significantly influenced the rheological properties of concrete mix, stabilised it and reduced the segregation. It was proved, that the concrete mix modified by VMA used in the optimal amount, featured the smallest scatter of concrete strength results. Besides, the Tukey's test showed that a reduction of the concrete compressive strength is possible to be statistically insignificant when compared to the reference level.

scholarly journals Effect of Formaldehyde to Phenol Ratio in Phenolic Beads on Pore Structure, Adsorption and Mechanical Properties of Activated Carbon Spheres

2019 ◽  
Vol 69 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Arjun Singh ◽  
Sanjeevan Aggrawal ◽  
Darshan Lal
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Activated Carbon ◽  
Pore Structure ◽  
Surface Area ◽  
Pore Volume ◽  
Bet Surface Area ◽  
Activation Process ◽  
Carbon Spheres ◽  
Activated Carbon Spheres

Phenolic beads (PBs) prepared from different formaldehyde to phenol (F/P) molar ratios were used as polymeric precursor for activated carbon. Activated carbon spheres (ACSs) have been produced from PBs via the physical activation process using carbon dioxide (CO2) as activating agent at 950 °C for different burn-off. The prepared ACSs were investigated for nitrogen adsorption, surface morphology and compressive strength by means of BET surface area analyser, scanning electron microscopy (SEM) and carbon and sphere tester techniques. The results indicated that the effects of F/P ratio observed, especially variation in the adsorption and mechanical properties. It was found that ACSs obtained from F/P ratio one showed the superior adsorption properties, possessed a high BET surface area in a range of 836 m2 g-1 to 3694 m2 g-1 with high pore volume (0.47 cm3 g-1 - 2.47 cm3 g-1) and 73-97 per cent microporosity. The BET surface area and pore volume increased, while the microporosity gradually decreased, with increasing the extent of burn-off. Compressive strength decreased with increasing F/P ratio as well as the extent of burn-off. ACSs upheld improved compressive strength (from 160 N mm-2 to 9 N mm-2) than those obtained from F/P ratio 2 and 3 in PBs. SEM studies of ACSs demonstrated well developed pore structure.

scholarly journals Evolution of Zeolite Crystals in Self-Supporting Faujasite Blocks: Effects of Hydrothermal Conditions

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1965 ◽  
Author(s):  
Liuliu Guan ◽  
Zhuangzhuang Wang ◽  
Duyou Lu
Keyword(s):  
Compressive Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Hydrothermal Treatment ◽  
Specific Surface Area ◽  
The Self ◽  
Hydrothermal Conditions ◽  
Average Pore ◽  
Characterization Methods ◽  
Fau Zeolite

In order to prepare self-supporting faujasite (FAU) zeolite, a self-supporting zeolite block was synthesized in situ by hydrothermal treatment of a metakaolin base geopolymer. The effects of hydrothermal conditions such as hydrothermal alkalinity, temperature and time on the phase composition, microstructure and mechanical strength of the hydrothermal samples were investigated and evidenced by a series of characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmet-Teller (BET). The results showed that a self-supporting faujasite block could be obtained by hydrothermal treatment of the geopolymer block in 2 M NaOH solution at 90 °C for 24 h, which had high crystallinity, regular morphology and high compressive strength. The self-supporting zeolite block had a compressive strength of 11.7 MPa, a pore volume of 0.24 cm3/g, and an average pore diameter of 7.86 nm. The specific surface area and the microporous specific surface area of the self-supporting faujasite blocks were 80.36 m2/g and 19.7 m2/g, respectively.

Sign in / Sign up

Export Citation Format

Share Document