Capillary Absorption Research Articles

Multi-objective optimization of cement-based systems containing marine dredged sediment

This study presents the integrated use of particle packing methodology and response surface methodology as an innovative mixture design for developing eco-friendly cement-based systems containing marine dredged sediment. The objective was to reduce the sand and cement contents of mortar mixtures for island applications, while maintaining the same properties as a reference mixture. The study examined three input variables for mixture design and optimization: sediment-to-total sand ratio ranging from 0.1 to 0.4, water-to-binder ratio ranging from 0.4 to 0.5, and cement paste content ranging from 0.35 to 0.45. As a result, three mixtures were developed based on three optimization objectives: (1) maintaining the same fresh and hardened properties as the reference (110 mm spread flow and 49.5 MPa strength); (2) maximizing the reduction of cement and sand contents with the use of a superplasticizer; and (3) maximizing the durability (as measured with the bulk electrical resistivity). The optimal mixture proportions showed reduced sand and cement contents up to 38 % and 15 %, respectively, with mechanical properties comparable to that of the reference. Moreover, capillary absorption and drying shrinkage of the optimized mixtures were reduced compared to the reference by up to 36 % and 16.5 %, respectively. It was evidenced that the combined use of mixture design methods can significantly contribute to the development of cementitious systems with balanced eco-efficiency and properties.

Influence of Nano-Silicon Dioxide in the Enhancement of Surface Structure of Public Filler and Properties of Recycled Mortar

This paper proposes a method of enhancing public filler (PF) with nano-SiO2 (NS) to prepare modified recycled aggregate mortar (RAM). The improvement effect of NS solution at different concentrations and immersion times on the macroscopic physical properties of recycled public fine aggregates (PFA) was investigated. Moreover, the effect of NS on the basic physical properties and durability of recycled mortar (RM) and the reinforcement mechanism of NS on recycled mortar was analyzed through various techniques. Results indicated that the modification effect of NS could remove loose cement mortar from the surface of PFA. It reacted with calcium hydroxide and calcite to generate nano-particles that could fill pores in PFA. The water absorption rate of PFA decreased to 9.3% when immersed in 2% NS solution for 72 h. There was no significant improvement in the mechanical properties of RM when the solution concentration and immersion time were increased. However, the compressive strength of RM prepared by modifying PFA with 2% NS was increased by about 21.9%, and the capillary water absorption and electric flux were reduced by 56.3% and 15.1%, respectively. Micro-analysis results showed that the volcanic ash effect of NS enabled it to react with Ca(OH)2 adhered to the surface of PFA, generating C-S-H and improving the interfacial bonding of PFA. Moreover, NS adsorbed on the surface of PFA dispersed into the freshly mixed cement slurry, which further enhanced the internal structure of PFA.

Evaluation of the effect of E-waste on the permeability properties of polymer concrete composites and their behavior in aggressive environments

The rapid increase in the number of electronic products worldwide, in terms of both variety and advanced technology, together with the decrease in costs, has led to the generation of a large amount of electronic waste (e-waste), which has significantly increased environmental pollution. This study was conducted to investigate the hypothesis that the adhesion of polymer binders and plastic origin e-waste will be more effective and stronger, and therefore have a positive effect on the permeability properties of polymer concrete and its behavior against aggressive solutions. For this purpose, quartz aggregates and gravel used as an aggregate in polymer concrete were replaced with 0%, 3%, 6%, 9%, 12% and 15% e-waste. In the study where unsaturated polyester resin was used as a binder, the changes in the permeability properties (capillary water absorption, rapid chloride permeability) of the e-waste polymer concrete and its behavior against aggressive solutions (acid and sulfate attacks) were evaluated after 7, 28 and 90 days. In addition, mechanical experiments were conducted and comparisons were made. After the control concrete, the highest compressive strengths were obtained from the polymer concrete specimens using 3% e-waste, measured as 59.05 MPa, 64.5 MPa and 73.05 MPa after 7, 28 and 90 days, respectively. The research showed that polymer concretes with capillary water absorption coefficient values close to zero after 90 days can be produced with using up to 9% e-waste. The use of e-waste as an aggregate in polymer concrete at 3%, 6% and 9% e-waste, in particular, produced concrete with a high resistance to acid and sulfate attacks. The hypothesis of the study was confirmed after extensive experiments.Graphical

Characterization and damage of the historic brick masonry of the Zákupy castle stables

Abstract A chemical-mineralogical analysis and mechanical tests of historical bricks were carried out as part of the construction-technical survey. The objective was to identify the causes of significant masonry decay. The ruined agricultural yard is a national cultural monument. Conservators believe that the historical importance exceeds that of the neighbouring castle. Stables were designed in 1650 by prominent Italian builders Giulio Broggio and Giovanni Domenico Orsi. The building has not been maintained since the conclusion of World War I. After removal from the masonry, the analyzed samples of bricks reached a very high, almost total degree of water saturation - 87-94%. Some bricks are heavily contaminated with nitrates and sulfates, infrared spectrometry analysis showed that calcium nitrate tetrahydrate is the most abundant of the nitrates. The determined average values of physical properties (bulk weight 1764 kg/m3, capillary absorption 13.6% by weight and open porosity 24% by volume) from samples under atmospheric pressure are comparable to the values of masonry bricks produced today. The results of the tests on the bricks from the Zákupy Castle stables construction demonstrate the high manufacturing quality of the masonry elements utilized. Based on the results of the analyses, it can be assumed that three degradation factors contribute to the observed damage to the bricks: high wetting of the masonry (almost total saturation of pores with water), which is most likely long-term lasting, frost cycles - repeated freezing and thawing of water in the bricks during the winter months, and repeated crystallization of water-soluble salts present in pores near the surface.

Experimental Study on Capillary Water Absorption Performance of Coral Sand Concrete in High-Salt Environment

Experimental Study on Capillary Water Absorption Performance of Coral Sand Concrete in High-Salt Environment

Performance and Accelerated Ageing of an Industrial Hydraulic Lime Mortar Applied on Different Substrates

Mortar that is typically employed for interior or exterior coatings can be characterised using laboratory-prepared specimens according to specific test standards; however, its performance undergoes changes following application on substrates. When selecting mortar, it is vital to anticipate its in-service behaviour after its application on substrates to make the most informed choice. Most of the research work carried out to date analyses the characteristics of mortar in laboratory specimens. Some studies analyse these characteristics after its application to support, but very few exist that compare both behaviours. With this objective in mind, this research determined the properties of mortar when cured within laboratory moulds and assessed the behaviour of the same mortar after application on diverse substrate types. This study specifically evaluated the behaviour of a pre-dosed hydraulic lime mortar when applied on concrete blocks, lightweight concrete blocks, concrete slabs, hollow ceramic bricks, and solid ceramic bricks. Later, this behaviour was compared to the same type of mortar hardened in laboratory moulds and the same type of mortar applied on substrates and subjected to accelerated ageing. Moreover, data from previous experimental work were used to compare the behaviour of the pre-dosed hydraulic lime mortar with that of pre-dosed cement mortar when applied on similar substrates. The research drew upon a comprehensive characterisation of the physical and mechanical parameters of mortar, revealing that the performance of these types of mortar undergoes significant changes after application on substrates under in-service conditions, mainly when applied on more porous substrates. It was concluded that the application of mortar to substrates increased bulk density, decreased open porosity, enhanced compressive strength, and resulted in faster capillary absorption. For mortars subjected to accelerated ageing, a notable reduction in water vapour permeability was observed, which was attributed to changes in the pore profile.

The influence of internal hydrophobization on the characteristics and durability of the cement-based materials

The presented study examined the effectiveness of internal hydrophobization and its impact on the basic properties of cement-based materials such as paste, mortar, and concrete. The obtained results clearly indicate that, in addition to a significant reduction of the capillary water absorption, internal hydrophobization also improves the durability of the material and provides protection against water also in case of cyclic freezing and thawing. Internal hydrophobization using an organosilicon admixture based on triethoxyoctylsilane also ensured an increase in the contact angle for water to over 90 and limited moisture sorption in the material. Moreover, the presented results indicate the interactions of the organosilicon compound with cement, which can be observed as changes in the amount of heat released during cement hydration, impact on the microstructure of the mortar, and a decrease in the compressive strength of the mortar and concrete. Nevertheless, internal hydrophobization by organosilicon compounds such as triethoxyoctylsilane is an effective and efficient method of protecting porous cementitious materials against water and moisture, even during cyclical exposure to negative temperatures

Enhancing the Durability of Pre-Cracked Concrete: The Crucial Role of Metakaolin and Ground Granulated Blast Furnace Slag

This study conducted a rigorous experiment to assess the strength and durability of pre-cracked concrete modifiedwith metakaolin (MK) and ground granulated blast furnace slag (GBFS). Three categories of hardened concrete werecompared to conventional concrete, focusing on key parameters such as compressive strength, mass loss, openporosity, water penetration, capillary water absorption, and drying shrinkage. The assessments were performed undertwo levels of compression damage and exposure to sulfuric acid (5% concentration). The results demonstrated asignificant long-term improvement in compressive strength by incorporating MK and GBFS, despite a reduction of upto 80% in the presence of sulfuric acid. The F10 formulation exhibited the best performance, highlighting the positiveimpact of additives on concrete durability. Replacing cement with MK and GBFS at a 10% level was identified as theoptimal design for sewer structures due to minimal shrinkage compared to other formulations.

Mechanical performance and permeability of low-carbon printable concrete

Common issues in 3D printed concrete arise due to its high cement content, processing requirements, and the lack of extensive research into its long-term performance. To this end, this study explores using supplementary cementitious materials from local regions to partially replace cement, aiming at reducing the carbon footprint. Various printable mixtures with different substitution rates are formulated, and corresponding mechanical and permeability tests are conducted. It is revealed that the compressive and flexural strengths of 3D printed concrete with low cement content were lower than the strength of cast concrete due to the construction process of printed concrete; the mechanical strength of 3D printed concrete showed prominent anisotropic characteristics. It was found that, compared with the other two sets of ratios, the higher contents of FA and GGBFS could effectively fill the pores of the printed concrete. Both the capillary water absorption and the content of chloride ions of the low-carbon mixture were significantly lower than that of the pure cement-printed specimens.

Research on the capillary absorption capacity of concrete of different particle sizes after high temperature based on nuclear magnetic resonance technology

Concrete is subjected to thermal stress and thermal loading in a high temperature environment, resulting in the expansion and contraction of internal pores, which adversely affects the stability and durability of concrete structures. To explore the effects of temperature and aggregate particle size on the capillary absorption capacity of concrete, the capillary absorption tests were carried out on the specimens with aggregate particle sizes of 1.25–2.5 mm, 2.5–5.0 mm and 5.0–10 mm after high temperature treatment at 300 °C, 400 °C and 500 °C.In this paper, The capillary absorption coefficient was measured by mass change method, and the migration change law and spatial distribution of water during capillary absorption were monitored by NMR technology, the changes in water content in different pores during water absorption were calculated by nuclear magnetic resonance T2 spectroscopy, and a method for calculating the capillary absorption coefficient based on T2 spectra was proposed. The results showed that the capillary absorption coefficient of the samples without high-temperature treatment decreased with increasing of particle size. The capillary absorption coefficient increases at 300 °C and decreases slightly at 400 °C. At 500 °C, the capillary absorption coefficient increases dramatically. This shows that at 500 °C, the durability of concrete is drastically affected. The capillary absorption coefficient calculated based on the T2 spectrum is linearly related to the results of the traditional weighing method. In this paper, the fractal geometry theory and regarding methods are used to deduce the relationship between the average capillary rise height and t12DT, and the rise rate is related to the pore structure. And the correctness of the model was verified by MRI. This study can provide theoretical guidance for the safety assessment of concrete structures after high temperature exposure.

A Comprehensive Experimental Study on the Physical Performance and Durability of Bamboo Bio-Concrete

In recent decades, the building sector has been moving toward promoting renewable raw materials to reduce greenhouse gas emissions associated with construction materials. One of the most valuable alternatives is the use of large-volume fractions of vegetable aggregates, leading to the development of bio-based cement mixture. A review of the recent scientific literature has shown that traditional design rules cannot be applied to bio-based cement mixtures. In this context, this study summarizes the results of a comprehensive experimental campaign aimed at unveiling the influence of bamboo particles on the physical properties and durability indicators of Bamboo Bio-Concrete (BBC) designed by applying a recent methodology proposed by the authors. The mixtures were produced using bamboo particles at a volumetric fraction of 45% and 50%. Fundamental properties such as density, thermal conductivity, capillary water absorption, and drying shrinkage were measured. The results obtained herein highlight the lightweight (density lower than 786 kg/m3) and insulating properties (thermal conductivity within 0.32 to 0.52 W/mK) of the BBC. The capillary absorption ranged between 2.40 and 2.83 g/cm2, whereas the drying shrinkage ranged between 2500 and 5000 µε. These properties indicate the feasibility of using this material in various applications in the construction sector.

The effect of chemical oxygen demand of domestic wastewater on workability, mechanical, and durability of self- compacting concrete

Due to worldwide water scarcity, especially in arid regions, and the substantial use of drinking water in concrete production, the consideration of gray water usage is growing. However, wastewater contamination adversely affects concrete's mechanical strength and durability, with Chemical Oxygen Demand(COD) as one of the indicator. In the present work, the effect of COD of different types of domestic wastewater on workability, mechanical, and durability properties of self-compacting concrete (SCC) with 400 kg/m3 and 440 kg/m3 of cement, and water-to-cement ratios of (w/c) 0.36 and 0.5 for 12 different SCC mixture designs were investigated. The results of the experiments indicated that increasing the COD of domestic wastewater negatively impacts the workability of fresh concrete. Additionally, as the COD of the wastewater increases, the compressive strength of SCC decreases at 7 and 28 days when using raw sewage, sewage sludge, and artificial wastewaters. However, by 90 days, the compressive strength showed no significant difference compared to SCC made with tap water. With increasing COD of wastewater, the 28-day tensile strengths of SCC decreased by 6–10 %. The COD of wastewater did not significantly affect the flexural strength. However, the fracture toughness, at a water-cement ratio (w/c) of 0.5, decreased with increasing COD, reaching a reduction of 36 % at a COD of 940 mg/L. As the COD concentration rises, water absorption increases. In SCC samples containing sludge water and raw sewage, capillary water absorption was at its maximum due to the presence of impurities, as well as organic and mineral materials.

Assessment of the properties of mortars made of sorel cement

The purpose of laboratory tests was to determine the effect of sodium silicate and selected hydrophobic agents on the basic physical parameters and freeze-thaw durability of mortars made with Sorel cement in variable proportions. In order to determine the mortars’ parameters, samples of the dimensions of 4x4x16 cm and boards of the diameters of 1x4x16 cm were prepared. Parameters such as water absorption, capillary absorption, compressive and flexural strength and frost resistance were tested. Mortar supplemented with sodium silicate in the quantity of 2.6% of all components demonstrated the best properties. None of the other hydrophobic agents that were used to mitigate the negative effects of water on Sorel cement mortars demonstrated such positive properties. Flexural strength tests of all mortar batches, performed on cuboid samples and boards of the thickness of 1 cm, demonstrated a similar improvement in strength. The lowest value of compressive strength was recorded for the reference batch at 46.6 MPa, whereas the highest value was recorded for the second batch containing sodium silicate, at 49.8 MPa. During the testing of frost resistance, the lowest reduction of compressive and flexural strength was recorded for the reference mortar and for mortar with sodium silicate. All mortars were varied in the MgO/MgCl2 ratio and the total amount of water, the observed effects may be caused by other variables. However it is possible to notice the positive effect of selected hydrophobic agents.

Closure to the discussion of “Water distribution characteristics of capillary absorption in internally cured concrete with superabsorbent polymers”

Closure to the discussion of “Water distribution characteristics of capillary absorption in internally cured concrete with superabsorbent polymers”

Impact of anionic surfactant-based foaming agents on the properties of lightweight foamed concrete

Due to its low density, high thermal insulation, and ability to contribute to energy saving, lightweight foamed concrete (LWFC) is a versatile material that finds use in a wide variety of contexts. The properties of foam are significantly influenced by the selection of surfactant and foam production parameters, which in turn impact the properties of LWFC. Therefore, the anionic foaming agent effect on the distinct properties of LWFC needs to be investigated to create a lightweight structure in modern days. This research aims to better understand the interactions between cement particles and anionic foaming agents, which produce stable and consistent aqueous foams because of their negative charge. Investigations were carried out on the effects of anionic foaming agents of LWFC features on the fresh state characteristics, mechanical behaviour, microstructure, and transport properties. In this investigation, four distinct types of anionic surfactants specifically sodium lauryl sulphate (SLS), alpha olefin sulfonate (AOS), sodium lauryl ether sulphate (SLES), and sodium alcohol ether sulphate (AES) were considered, with all mixes maintaining a consistent cement-to-sand ratio and identical amounts of foaming agents. The fresh state testing exhibits that AOS-based LWFC may be preferred when lower setting time and spreadability, as well as a higher density, are required. The AOS-based LWFC exhibits lower capillary sorption, water absorption, and gas permeability than SLES, SLS, and AES-based LWFC. At 28 days, about 91–96 % of the compressive, tensile, and flexural strength of AOS-based LWFC is obtained for SLS, SLES, and AES-based LWFC. In addition, at the same curing age, the results for modulus of elasticity were over 6 % higher in the AOS-based LWFC mixture than in the other mixes. The pore structural and microstructural behavior revealed that AOS and SLS foamed-based LWFC exhibit a considerable reduction of macropores, or long capillaries, with diameters less than 500 µm, which can be used in the lightweight structure in modern days. This research emphasizes the significance of selecting the appropriate foaming agents to optimize the mechanical and transport properties of LWFC, which provides substantial benefits for contemporary construction practices.

Discussion of “Water distribution characteristics of capillary absorption in internally cured concrete with superabsorbent polymers”

In March 2024 Construction and Building Materials published “Water distribution characteristics of capillary absorption in internally cured concrete with superabsorbent polymers”, which claims to present a water distribution model characterising the spatiotemporal moisture content evolution in internally cured concrete with superabsorbent polymers during capillary absorption. This discussion, considered a post-publication critique, establishes that the paper’s water distribution model conflicts with the paper’s capillary absorption tests. While the model is based on the premise of the square-root-of-time behaviour of capillary absorption, the tests do not demonstrate that square-root-of-time behaviour. This critique in addition questions the paper’s forthright application of the power-law diffusivity expression with exponent 4, given that its validity for the paper’s materials has not been verified. It is shown that different but equivalent diffusivity expressions lead to different moisture diffusivities at lower moisture contents.

New water-based hybrid materials for the protection against water and consolidation of stone monuments

This research aims to develop a multifunctional, water-based product for protecting and consolidating stone materials. A new synthesis strategy using water-diluted silane formulations, composed of TEOS and an alkyl monomeric silane (ETES) or a polymeric siloxane (PDMS), homogenized by ultrasonic irradiation was followed to produce hybrid networks and overcome the limitations of current hydrophobic consolidants.These formulations gave rise to low dry residues and hydrophobic surfaces on various stones, including on low and high porosity stone varieties. Despite some formulations originated cracked films, optimal concentrations of ETES and PDMS showed high protection levels against capillary water absorption with minimal impacts on the color and water vapor permeability of the stones. Besides demonstrating the initial efficacy of these new hybrid materials in modifying the inherent hydrophilic and water-absorbing properties of stones, this work further confirmed their ability to penetrate within the stone pores and their initial efficacy in consolidating porous stones.Thus, new water-based multifunctional hybrid materials capable of consolidating and protecting various types of stones from water-related damage have been developed. These novel materials align with both technical and environmental requirements.

Synergistic effects of GGBFS and EAFS on rheology, mechanical properties, and durability of self-compacting concrete: Experiments, predictions, and life cycle assessment

With the aim of reducing the use of natural resources, this research evaluated the behavior of self-compacting concrete (SCC) containing granulated blast furnace slag (GGBFS) powder instead of limestone powder, GGBFS fine aggregate instead of natural fine aggregate, and electric arc furnace slag coarse aggregate (EAFS) instead of natural coarse aggregate. The evaluation included a comprehensive assessment of fresh concrete properties, compressive strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, and capillary water absorption. In addition, equations were proposed to predict the compressive strength of concrete in terms of the type and percentage of material replacement and curing time. Finally, the environmental effects of the concrete mixtures were studied, which fills a significant research gap. The results showed that with the optimal use of the mentioned substitute materials in concrete, the properties of fresh concrete, hardened concrete, and durability are improved. Using 45% GGBFS powder, 30% GGBFS fine aggregate, and 45% EAFS coarse aggregate, the concrete properties improved in comparison to the reference concrete. However, the results of the life cycle assessment showed that this mix design has more harmful effects on the environment than other designs of the present research. It should be noted that if these materials were not used in concrete, the same amount of damage would have been occurred due to their disposal.

EVALUATION OF PROPERTIES OF MASONRY MORTARS BLENDED WITH CERAMIC WASTE POWDER

<p class="ABSTRACT">Aiming to meet the principals of the modern circular economy, this study explores the possibility of using locally available waste materials in the production of innovative, eco-friendly mortar for masonry. The eco-binder, applied as a substitute for cementitious material, is ceramic waste powder (CWP) generated during the production of ceramic industry elements. Within the experimental program, compositions of twelve types of masonry mortars were designed with volumetric ratios of solid components 1:1:5, 1:0.7:4.2, and 1:1:4 (cement + eco-binder/lime/sand), varying the percentage of cement replacement with ceramic powder (up to 80%). The basic properties of masonry mortars were tested, including consistency, compressive strength, flexural tensile strength, capillary water absorption, and adhesion. The test results indicate that ceramic waste powder can be successfully used as a partial replacement for cement up to high substitution levels, yielding more sustainable masonry mortars for use in load-bearing or non-load-bearing masonry structures.</p>

SOME PHYSICAL PROPERTIES OF LIGHTWEIGHT MORTARS WITH EXPANDED VERMICULITE

<p class="ABSTRACT">Expanded vermiculite was added to the cement-lime mortar at 10%, 20% and 30%, which reduced the density of the hardened mortar (HM) without expanded vermiculite (EV) by an average of 8,3% for the HM with 10% EV, 14,7% for the HM with 20% EV and 24,2% for the HM with 30% EV. Compressive and flexural strength and static modulus of elasticity were investigated and the relationships between these properties were determined. The effect of the added amount of EV on: total porosity, air void content and capillary suction of HM according to SIA 262, Appendix A; capillary water absorption; gas permeability and air permeability; water permeability and internal freeze/thaw resistance up to 200 cycles was investigated and determined.</p>