Drying Shrinkage Of Concrete Research Articles

A Study on a New Method for Simultaneous Internal Curing and hydrophobic in Concrete

The high hydrophilicity and permeability of concrete caused by many pores and hydroxyl groups produced by cement hydration are the main factors leading to dry shrinkage, cracking, and poor corrosion resistance of concrete. Giving concrete internal curing and hydrophobicity is an effective measure to solve the above problems. In this paper, a new idea and preparation method for an organic combination of hydrophilic and hydrophobic materials are proposed to improve the service life of concrete structures. Furthermore, the combined effects of hydrophilic and hydrophobic amphoteric materials (HAM) on the mechanical properties, internal curing properties, and hydrophobic properties of concrete were comprehensively investigated. In addition, the physical and chemical action mechanisms were analyzed in conjunction with microscopic tests. The results indicated that HAM rapidly released water within 3-7 days before concrete curing, and then slowly released water accompanied by the release of hydrophobic materials, gradually from hydrophilic to hydrophobic properties; The addition of HAM did not reduce the mechanical properties of concrete, which solved the problem of low compressive strength of integral hydrophobic concrete; The addition of HAM reduced the drying shrinkage of concrete by 154.12%, increased the contact angle to 96°, and decreased the water absorption rate by 36%, allowing the concrete to achieve better internal curing and a hydrophobic effect. The preparation of this material can open up a new way to solve the hydrophilic and hydrophobic properties required by concrete at the same time, and fill the gap that concrete can not balance hydrophilic and hydrophobic properties.

Mesoscopic simulation of concrete drying shrinkage with hydration kinetics

Shrinkage-induced cracking significantly impacts the durability of mass concrete structures. Quantitatively evaluating drying shrinkage of concrete proves challenging due to the time-consuming experiments and overlooked microstructure changes during the hydration process. To address this concern, this study initially characterized the long-term hydration products and microstructure of low-heat Portland cement (LHPC) through microstructural experiments. Subsequently, a novel high-resolution mesoscale framework is developed to investigate the drying shrinkage with hydration kinetics. High-resolution models consist of realistic-shaped aggregates are validated by the aggregate morphology and gradation parameters of core sample from mass concrete. Concurrently, the quantitative effects of internal and external factors on LHPC drying shrinkage are explored. Results indicated that LHPC possesses a denser microstructure, lower porosity, higher carbonation resistance, and 20% lower drying shrinkage compared to moderate-heat Portland cement, suggesting promising applications. Furthermore, experimental and computational findings suggested that increasing aggregate volume, controlling aggregate morphology, and adjusting curing time and humidity could be employed to reduce and manage drying shrinkage, ensuring concrete structure durability.

Enhancing the mechanical and thermal properties of foam concrete by incorporating glass lightweight microspheres

The inferior mechanical strength and thermal resistance of foam concrete limited its application in thermal insulation engineering. This study focused on enhancing the mechanical strength and thermal resistance of foam concrete by incorporating glass lightweight microspheres (GLM) to partially replace foam. The roles of GLM in foam concrete were investigated through physical, mechanical, and thermal properties tests. The improvement mechanism behind the mechanical strength and thermal resistance was further revealed. Results indicated that the addition of GLM enhanced mechanical strength of foam concrete by promoting hydration reaction, optimizing pore structure, and improving GLM-paste interfaces. The mechanical strength of foam concrete with 20 % GLM increased by about 40 %. Moreover, GLM improved the residual compressive strength after exposure to 800°C, with an enhancement of 39.8 %. The inclusion of GLM reduced the risks of crack formation, densified the paste, and strengthened the foam wall due to its hollow structure, pozzolanic reactivity, melting and filling effects, and the phase transformation of additional C-S-H into well-packed wollastonite. Additionally, GLM with closed and isolated pores reduced the drying shrinkage and water absorption rate of foam concrete. The finding suggests that incorporating an appropriate amount of GLM can produce high-strength, low-density, and thermal-resistant foam concrete.

Effect of graphene oxide on mechanical, deformation and drying shrinkage properties of concrete reinforced with fly ash as cementitious material by using RSM modelling

The industrial production of cement contributes significantly to greenhouse gas emissions, making it crucial to address and reduce these emissions by using fly ash (FA) as a potential replacement. Besides, Graphene oxide (GO) was utilized as nanoparticle in concrete to augment its mechanical characteristics, deformation resistance, and drying shrinkage behaviours. However, the researchers used Response Surface Methodology (RSM) to evaluate the compressive strength (CS), tensile strength (TS), flexural strength (FS), modulus of elasticity (ME), and drying shrinkage (DS) of concrete that was mixed with 5–15% FA at a 5% increment, along with 0.05%, 0.065%, and 0.08% of GO as potential nanomaterials. The concrete samples were prepared by using mix proportions of design targeted CS of about 45 MPa at 28 days. From investigational outcomes, the concrete with 10% FA and 0.05% GO exhibited the greatest CS, TS, FS, and ME values of 62 MPa, 4.96 MPa, 6.82 MPa, and 39.37 GPa, on 28 days correspondingly. Besides, a reduction in the DS of concrete was found as the amounts of FA and GO increased. Moreover, the development and validation of response prediction models were conducted utilizing analysis of variance (ANOVA) at a significance level of 95%. The coefficient of determination (R2) values for the models varied from 94 to 99.90%. Research study indicated that including 10% fly ash (FA) as a substitute for cement, when combined with 0.05% GO, in concrete yields the best results. Therefore, this approach is an excellent option for the building sector.

Effect of titanium dioxide as nanomaterials on mechanical and durability properties of rubberised concrete by applying RSM modelling and optimizations

The use of rubber aggregates derived from discarded rubber tyres in concrete is a pioneering approach to replacing natural aggregate (NA) and promoting sustainable building practices. Recycled aggregate in concrete serves the dual purpose of alleviating the accumulation of discarded rubber tyres on the planet and providing a more sustainable alternative to decreasing natural aggregate. Due to fact that the crumb rubber (CR) decreases the strength when used in concrete, incorporating titanium dioxide (TiO2) as a nanomaterial to counteract the decrease in strength of crumb rubber concrete is a potential solution. Response Surface Methodology was developed to generate sixteen RUNs which contains different mix design by providing two input parameters like TiO2 at 1%, 1.5%, and 2% by cement weight and CR at 10%, 20%, and 30% as substitutions for volume of sand. These mixtures underwent testing for 28 days to evaluate their mechanical, deformation, and durability properties. Moreover, the compressive strength, tensile strength, flexural strength and elastic modulus were recorded by 51.40 MPa, 4.47 MPa, 5.91 MPa, and 40.15 GPa when 1.5% TiO2 and 10% CR were added in rubberised concrete after 28 days respectively. Furthermore, the incorporation of TiO2 led to reduced drying shrinkage and sorptivity in rubberized concrete, especially with increased TiO2 content. The study highlights that TiO2 inclusion refines pore size and densifies the interface between cement matrix and aggregate in hardened rubberized concrete. This transformative effect results in rubberized concrete demonstrating a commendable compressive strength comparable to normal concrete.

Drying shrinkage properties of fiber-reinforced alkali-activated slag and their correlations with microstructure

The superior strength, durability, and environmental sustainability of alkali-activated slag (AAS) systems renders it a viable alternative to those based on Portland Cement (PC). However, drying shrinkage in AAS systems is a highly complex process requiring extensive testing. Several studies have reported the incorporation of fibers to AAS systems as an effective way not only to enhance its strength but also to reduce its drying shrinkage, but the information is scattered. In pursuance of this objective, the present study investigates the impact of incorporating steel, polypropylene, polyvinyl alcohol and glass fibers at varying volume fractions from 0.1% to 0.3% on both mortar and concrete AAS specimens. According to the findings, incorporating fibers to AAS concrete increased its compressive strength by up to 13% when compared to the plain mix. A higher volume fraction of 0.3% for steel and glass fiber inclusions significantly minimized the drying shrinkage of AAS concrete by 27% and 31%, respectively. However, due to the increased heterogeneity and subsequent void formation in fiber-reinforced AAS systems, it was noted that the mass loss resulting from the loss of moisture is greater in these cases. Despite the greater mass loss at earlier ages, the fibers in AAS specimens demonstrated their ability to restrain the shrinkage strains. The microstructural studies, which distinctly depict the morphology of AAS paste and the interaction between the fibers and matrix, further validate these conclusions.

A Simplified Mesoscale Approach for the Prediction of Drying Shrinkage of Concrete

A Simplified Mesoscale Approach for the Prediction of Drying Shrinkage of Concrete

Drying shrinkage of geopolymeric recycled aggregate concrete

In this work, the drying shrinkage behavior of geopolymeric recycled aggregate concrete (GRAC) was studied with attention devoted to the mass loss, drying shrinkage strain, and sensitivity of drying shrinkage to water loss. The GRACs were prepared based on different fly ash/slag ratios and various dosages of recycled aggregate. Also, two types of curing regimes were employed, including ambient and heat curing. Additionally, the drying shrinkage strain development of GRACs was fast in the first 28 days and then slowed down with time. Recycled aggregate dosage increased the dry shrinkage strain while increasing the slag content and curing temperature reduced the drying shrinkage strain. Analogously, the sensitivity of drying shrinkage to the mass loss was raised under high recycled aggregate replacement ratios, whereas decreased when the slag content increased or heat curing was employed. Based on the test results, a prediction model was established for the drying shrinkage of GRACs, in which the factors of recycled aggregate replacement ratio, slag content, and curing regime were involved.

Steel slag's effect on concrete mechanical properties and durability

The utilization of steel slag as a mineral additive in concrete has been the subject of research aimed at assessing its impact on concrete's properties such as compressive strength, chloride penetrability, drying shrinkage, and resistance to carbonation. In this study, two different conditions were considered: constant water-binder ratio and compressive strength after 28 days. The results showed that increasing the amount of steel slag in concrete decreased its compressive strength, particularly its early strength, permeability, and ability to resist carbonation under constant W/B conditions. At lower water-binder ratios, however, the adverse effects of steel slag on the strength of compression, penetrability, and the carbonation resistance of concrete were less pronounced. When the W/B was high early in the drying process, steel slag accelerated shrinkage, but it had no impact on the final shrinkage at 90 days. The impact on concrete drying shrinkage was minimal at low W/B. Under continuous 28-day compressive strength conditions, it was also discovered that concrete containing steel slag had a lesser early strength and a higher late performance than pure cement concrete. It was found that the penetrability, carbonation resistance, and drying shrinkage of steel slag concrete were comparable to those of regular and pure cement concrete. This research highlights the potential of steel slag as a mineral additive in concrete production, but its use must be carefully considered to ensure optimal results.

Formulation of Drying Shrinkage in Concrete Based on Interpretation of Machine Learning Model

Formulation of Drying Shrinkage in Concrete Based on Interpretation of Machine Learning Model

Study of the Effect of Plastic Aggregates on Drying Shrinkage and Expansion of Concrete

The aim of this work was to propose a possibility of using plastic aggregates from waste to reduce the shrinkage and expansion observed in concrete. The process of obtaining plastic aggregates was presented. Natural aggregates were partially substituted by plastic aggregates in the percentages: 0%, 5%, 10%, 20% and 30%. Drying shrinkage, water absorption and expansion tests were carried out on three families of concrete: control concrete (BT), concrete with addition of BAgP-PEHD high-density polyethylene plastic aggregate and with polyvinyl chloride BAgP-PVC. Given the slow appearance of the internal sulfate attack (ISA), an experimental technique was proposed to accelerate the appearance of this pathology. This technique involves heat treatment which stimulates the heating of the concrete at a young age, followed by a cycle of drying and cooling and ends with total immersion in water. The method of measuring expansions through sample image correlation was also proposed. The results showed an increased skrinkage of BAgP-HDPE compared to BT. On the other hand, a significant decrease in shrinkage was observed in BAgP-PVC samples. Water absorption increased in BAgP-HDPE and BAgP-PVC compared to BT. Greater expansion was observed at the cement paste-plastic aggregate interface than at the cement paste-natural aggregate interface. Given these properties, BAgP-PVC can be recommended for paving surfaces exposed to the hard weather conditions.

Long-Term Behavior of Concrete Containing Wood Biomass Fly Ash

Wood biomass is widely used in the European Union as a fuel for the production of heat and electrical energy, generating a considerable amount of ash. The disposal of ash, especially its finest fraction, requires proper engineering solutions, since these particles contain heavy metals and caneasily pollute soil, groundwater, or air. In this work, wood fly ash with a high amount of pozzolanic oxides and one with a high CaO content were used in concrete as a 15% and 30% cement replacement. Incorporation of wood ash in concrete reduced the 28-day compressive strength of concrete by up to 37%, which was attributed to the low stiffness of the wood ash particles, while the 2-year compressive strength indicated very low pozzolanic reactivity. The capillary absorption of concrete increased with the increase in the ash content, but almost no influence on the gas permeability was observed. Wood fly ash with high CaO content reduced the drying shrinkage of concrete by up to 65% after 1 year. In a mix with 30% of high CaO fly ash, swelling occurred in the first days of hydration, which was attributed to the volume expansion due to the formation of portlandite and brucite, but did not lead to cracking or a decrease in long-term compressive strength.

Predicting transverse crack properties in continuously reinforced concrete pavement

Transverse crack properties (crack spacing and crack width) are important indicators of service life performance of continuously reinforced concrete pavements (CRCP). Crack properties are related to concrete material properties, reinforcement ratio, interface friction between both the concrete-base layer and concrete-steel, and the local climatic conditions. An improved analytical model with a bilinear concrete-base friction relationship is presented to predict crack spacing and crack width from concrete drying shrinkage and temperature contraction. The proposed 1D model was validated with test section data from a continuously reinforced concrete beam resting on asphalt base layer, which contained two reinforcement ratios, a standard paving concrete, and a lightweight aggregate concrete. A sensitivity study of model determined the bond stiffness coefficient between the concrete and reinforcement, bar spacing and diameter, elastic modulus of the reinforcement, and concrete drying shrinkage had the greatest impact on both crack spacing and crack width.

Drying shrinkage of one-part alkali-activated slag concrete

The aim of this study was to evaluate the drying shrinkage of one-part alkali-activated slag concrete (AASC) for up to 180 days that is influenced by mix design parameters. A total of 24 mix designs for AASC and one for OPC concrete were made and cured in two different environments. The impacts of mix design parameters including water to binder ratio, silica fume to binder ratio, alkaline activator to slag ratio, and two curing regimes, in water and sealed plastic bag, on drying shrinkage were investigated, using experimental tests and SEM analysis. The results showed nearly 75% of the 180-day shrinkage was reached within 20 days. The results also revealed that the addition of silica fume considerably reduced drying shrinkage magnitude. AASC samples cured in sealed plastic bags resulted in at least a 5.9% increase in drying shrinkage. The maximum drying shrinkage was observed in a mix design containing the highest water to binder ratio and zero silica fume content regardless of curing type. The results indicated that the application of silica fume as a co-binder led to a considerable reduction in the drying shrinkage.

Theoretical Prediction of Drying Shrinkage of Concretes Containing Fine Recycled Aggregate

Theoretical Prediction of Drying Shrinkage of Concretes Containing Fine Recycled Aggregate

Mechanical Properties of Basalt-Based Recycled Aggregate Concrete for Jeju Island.

Recycled aggregate is essential to protect Jeju Island’s natural environment, but waste concrete, including porous basalt, is a factor that lowers the quality of recycled aggregate. Therefore, an experiment was conducted to analyze the properties of concrete application of basalt-based recycled aggregate (B-RA) through quality improvement. The absorption of the B-RA ranged from 3–5%; restricting its absorption to less than 3% was challenging owing to its porosity and irregular shape. However, the increase in the solid volume percentage of the concrete when replacing 25 or 50% of fresh basalt aggregate with recycled basalt aggregate improved the mechanical performance of the concrete, especially at 25%, for which a compressive strength of 55.9 MPa and modulus of elasticity of 25.9 GPa exceeded those of concrete with fresh basalt aggregate. Moreover, increasing the replacement ratio of the fresh basalt with recycled aggregate reduced the slump and decreased the air content, consequently increasing the concrete drying shrinkage. However, the replacement of fresh basalt aggregate with recycled basalt aggregate unaltered the mechanical performance of the concrete. The results indicate that efficient use of recycled aggregates can yield superior performance to that of fresh basalt, irrespective of aggregate quality.

Experimental studies and drying shrinkage prediction model for concrete containing waste foundry sand

Concrete being most extensively used construction material all over the globe has resulted in the over-exploitation of natural resources such as river-sand and gravels. Meanwhile, advancing industries and increasing population have also lead to an increased generation of waste materials. Many of these waste materials have the potential to be used in concrete. This study has investigated the effect of one such waste material referred to as Waste Foundry Sand (WFS) on the properties of concrete. Many researchers have studied the effect of WFS on the mechanical properties of concrete. However, no consensus has been reached yet and very contradictory results have been reported. Moreover, shrinkage of concrete containing WFS has not received much of the researchers’ attention and very limited literature is available related to this property. This study explores the workability, compressive strength, split tensile strength and drying shrinkage of such concretes. WFS was used as partial replacement of fine aggregate and the replacement levels were varied from 0 to 50% in equal increments of 10%. It was observed that the compressive strength and split tensile strength of concrete decreased with the addition of WFS. However, the mix WFS3 (30% WFS) showed the strength very similar to that of control concrete. A significant increase of 16.7%, 23.44%, 29.05%, 36.35% and 45.18% with respect to control concrete at the age of 28 days was observed in the magnitude of drying shrinkage when the amount of WFS in concrete was varied from 10 to 50%. Furthermore, it was seen that the available shrinkage prediction models could not be applied to the concrete containing waste foundry sand. Hence, a multivariable regression model inspired by ACI-209 model was developed for prediction of drying shrinkage in concrete. The proposed model included the parameters related to drying age and percentage of WFS in concrete and gave a high value of the coefficient of regression (R 2 ) indicating the effectiveness of the proposed model. • Incorporation of waste foundry sand (WFS) in concrete reduced the compressive strength and split tensile strength. • Least reduction in strength was observed in the mix containing 30% WFS as a replacement of river sand. • Drying shrinkage of concrete increased when WFS was added. • A multi-regression model with high regression coefficient was developed to predict the shrinkage in concrete containing WFS.

Effect of waste marble powder and rice husk ash on the microstructural, physico-mechanical and transport properties of foam concretes exposed to high temperatures and freeze–thaw cycles

An experimental program was performed to evaluate the impact of rice husk ash (RHA) as cement replacement and waste marble powder (WMP) as sand replacement on the microstructural, mechanical and transport properties of foamed concrete exposed to high temperature and freeze–thaw cycles. For this, Portland Cement (PC) was replaced by RHA at 10% and 20%wt of binder and silica sand was replaced by WMP at 25% and 50%wt of fine aggregates to cast foamed concrete mixtures. Two different foam contents of 40 kg/m3 and 80 kg/m3 were used in the production of foamed concretes with water/binder (w/b) ratio of 0.70. Two reference mixtures were produced from silica sand and without RHA at each foam content. Other foam concretes were fabricated from 25% and 50% WMP instead of silica sand and 10% and 20% RHA instead of cement. Fresh properties of mixtures were evaluated by performing slump test. Transport properties of foam concretes were investigated, including porosity, sorptivity and water absorption after 90 days curing. Mechanical properties of foam concretes were investigated, including compressive and flexural strength ultrasonic pulse velocity (UPV) after 7, 28 and 90 days. Drying shrinkage and thermal conductivity of concretes were also studied after 90 days. Durability of concretes were also investigated after exposure to the temperature of 200, 400, 600 and 800 °C and freeze–thaw (F-T) cycles of 100 and 200 in addition to microstructure investigations. Results show that 10% RHA as cement substitute and 50% WMP as sand substitute give optimum percentage especially at late-age of 90 days at foam content of 40 kg/m3. The lowest drying shrinkage and sorptivity were obtained by using 10%RHA and 25%WMP. The results also indicate that water cooled specimens showed more strength loss than air cooled specimens after 200 °C. The worst F-T performance was obtained for the mixture containing 10% RHA and without WMP by 43.8 and 59.8% strength reductions.

Experimental Study on Early Drying Shrinkage of Self-compacting Barite Concrete

In this paper, raw materials such as fly ash-S95 grade mineral powder composite mineral admixture, barite coarse and fine aggregate and polycarboxylic acid water reducer are selected to successfully formulate C30 self-compacting barite concrete with good performance. It also analyzes the development law of early drying shrinkage of self-compacting barite concrete with age, and discusses the effects of fly ash and slag mixing ratio and water reducer content on concrete work, compressive strength and early drying shrinkage. The results show that: the drying shrinkage of self-compacting barite concrete develops rapidly within 1 day of age, and the drying shrinkage rate at 1 day accounts for 50% to 66% of that at 7 days of age, and then the growth trend is slow; as the proportion of fly ash increases, the performance of the concrete mixture improves. While the strength of concrete decreases in the early and mid-term, the strength gradually increases in the later period, and the shrinkage strain of concrete in the early stage also increases significantly; the proper amount of water-reducing agent can greatly improve the fluidity of the mixture. In the dosage range of 1.2%~1.4%, with the increase of the amount of water reducing agent, the compressive strength first increases and then decreases, reaching the maximum when the dosage is 1.3%, and the early drying shrinkage strain of concrete increases slightly.

Increasing the crack resistance of high-strength self-compacting concrete

The object of research is high-strength self-compacting concrete, which does not require additional vibration during laying. One of the most problematic issues of high-strength self-compacting concretes is increased cracking, associated with large shrinkage deformations of such concretes and their fragile destruction.
 A decrease in shrinkage deformations of concrete was established when part of the cement was replaced to mineral additives. This effect is explained by a decrease of the cement content and, accordingly, a decrease of the chemical component of the autogenous shrinkage of concrete, and an increase of the adsorptive binding of capillary moisture by mineral additives, with reduces the physical drying shrinkage of concrete. In this case, the type and dispersion of the used mineral additive can affect to the shrinkage deformations of concrete. A significant decrease in shrinkage deformations when using metakaolin is explained by an increase the amount of ettringite as a result of the reaction of active metakaolin Al2O3 with two-water gypsum of cement. It was found that the replacement of cement to 10 % of mineral additives leads to a decrease in the value of the critical stress intensity factor (SIF), which is compensated by a decrease of the fragility of concrete fracture (an increase of the area of microplastic deformations). At the same time, the type of mineral additive used does not affect to the value of the critical stress intensity factor, but significantly affects to the fragility of fracture of concrete samples. The introduction of 10 % mineral additives (to replace cement) had a positive effect on the retention of flow of self-compacting concrete mixes; the best results according to this criterion were observed when using silica fume, fly ash and limestone. All mineral modifiers, except for silica fume, led to a decrease of the compressive strength of high-strength concretes on all terms of hardening. In the case of the tensile strength of concrete at bending and splitting, with the introduction of silica fume, metakaolin and fly ash, a positive effect was observed compared to the base composition without additives.
 Comprehensive accounting of the results obtained will allow a reasonable approach to the design of high-strength self-compacting concretes with increased crack resistance.