Workability Of Mixtures Research Articles

Influence of Polymer Fibers on the Structure and Properties of Modified Variatropic Vibrocentrifuged Concrete.

The application of polymer materials in concrete structures is widespread and effectively used. However, there is a lack of a systematic knowledge base about the structure formation and properties of variatropic vibrocentrifuged modified fiber-reinforced concrete. The purpose of this work is the investigation of the influence of polypropylene (PF) and basalt fiber (BF) and modification with microsilica (MS) on the properties of variatropic concretes obtained using the synthesized vibration centrifugation technology. Test samples were made using vibration centrifugation technology, followed by sawing. Various types of fiber reinforcement were studied, both individually and in combination. To determine the degree of effectiveness of each recipe solution, the following main characteristics were monitored: the density and workability of concrete mixtures; the density of hardened composites; compressive strength (CS); bending strength (BS); water absorption (WA). In variatropic vibrocentrifuged concrete, the greatest efficiency is achieved with dispersed BF reinforcement in an amount of 1.5%. Compared to the control composition, the increase in CS was 8.50%, the increase in BS was 79.17%, and WA decreased by 27.54%. With PF reinforcement, the greatest effect was recorded at a dosage of 1.0%. The increase in CS was 3.16%, the increase in BS was 10.42%, and WA decreased by 17.39%. The MS modification showed the best effect with 8% replacement of part of the Portland cement. The increase in CS was 17.43%, the increase in BS was 14.58%, and WA decreased by 33.30%. The most effective and economically rational formulation solution for vibrocentrifuged concrete is combined fiber reinforcement in combination with the MS modification in the following quantities: BF-1.0%; PF-0.5%; MS-8%. The increase in CS was 22.82%, the increase in BS was 85.42%, and WA decreased by 37.68%.

Optimization and mechanism analysis of a compound additive for unfired bricks made of construction and demolition wastes

Construction and demolition waste (CDW) was fully exploited to prepare high-strength and low-cost unfired bricks. A compound additive consisting of sodium silicate, microsilica powder, an early-strength water reducer, and wood fiber was incorporated into the bricks. Tests (compressive tests, freeze–thaw cycle tests, and scanning electron microscopy (SEM)) were carried out to determine the effect of the contents of the additive components on the properties (the strength, softening coefficient, freezing resistance, hydration products, and microscopic morphology) of unfired bricks of different curing ages. The experimental results were used to determine the optimum ratio of the components and the hydration mechanism. The optimized compound additive considerably improved the mechanical properties and crack resistance of the bricks, where the optimum content was found to be only 3.15% of the CDW dry mass. Compared with unfired bricks with no additives, unfired bricks with the optimized compound additive exhibited increases in the 1- and 28-day compressive strengths and softening coefficient of up to 66.8%, 65.9%, and 8.46%, respectively (corresponding to values of 8.46 MPa, 29.36 MPa, and 0.934, respectively) and a decrease in the freeze–thaw strength loss rate of 61.38%. Incorporating the compound additive into the unfired bricks considerably reduced the environmental impact. The SEM micrographs showed that the compound additive increased the silicon-to-calcium ratio and workability of the preparation mixture, increased the hydration rate, promoted the conversion of calcium hydroxide in the product to a C–S–H gel, and enhanced the density and strength of the hydration product.

Influence of Filler Materials on Bituminous Mastic Rheology at High Temperatures

The mixing and compaction temperatures of the bituminous mixture are determined by the viscosity of the binder. It was always a concern to understand the influence of the type of filler on the workability of the bituminous mixture. The interaction of the filler with the bitumen plays a key role in this. The inert filler has a physical interaction with the binder, and the active filler will have both a physical and chemical interaction. Based on the type of interaction, the viscosity and shear thinning characteristics of the mastic (binder + filler) change, which will hence influence the workability of the bituminous mixture. An experimental investigation is conducted to measure the viscosity of the mastic with two types of filler, one chosen from the active filler category (hydrated lime) and another from the inert filler category (quarry dust). A shear rate sweep experiment was carried out within the temperature range of 100 to 160 °C to analyze the Newtonian and shear thinning responses of the mastic. Results indicate that, for an equivalent weight proportion of the filler, mastic containing quarry dust exhibited elevated Newtonian viscosity and zero-shear viscosity (as predicted using the Carreau Yasuda Model). Additionally, quarry dust mastic demonstrated a higher rate of shear thinning. Consequently, the beneficial effect of shear thinning during the compaction of bituminous mixtures has the potential to enhance workability and streamline the compaction process. Doi: 10.28991/CEJ-2024-010-02-013 Full Text: PDF

The combination of conventional Roller Compacted Concrete (RCC) with the substitution of fly ash for fine aggregate replacement

This study aimed to investigate the characteristics of roller-compacted concrete when fine aggregate is replaced with fly ash. The investigation focused on assessing workability, compressive strength, flexural strength, and split tensile strength of the concrete mixtures. Four testing methods were employed, including the slump test for workability assessment, the compression test for determining compressive strength, the flexural test for evaluating flexural strength, and the split tensile test for measuring split tensile strength. The fly ash used in this project was sourced from the powerplant in Malaysia. Various fly ash contents, specifically 0%, 55%, 65%, and 75%, were utilized to replace the fine aggregate. The concrete mixtures were subjected to water curing for 7, 14, and 28 days before testing. Following the mixing process using a concrete mixer, the mixtures underwent a slump test to evaluate their workability. It was observed that the workability of the concrete decreased as the percentage of fly ash used to replace the fine aggregate increased. Mixtures with fly ash exhibited zero slump, while the control mixtures displayed true slump. Subsequently, compression, flexural, and split tensile tests were conducted after 7, 14, and 28 days of water curing. In terms of compression strength, an increase in fly ash content resulted in higher compressive strength in the concrete mixtures. The mixture with 65% fly ash content demonstrated the highest compressive strength at 49.84 MPa. Regarding flexural strength, the concrete with 75% fly ash content exhibited the highest value, measuring 5.45 MPa. However, for split tensile strength, the concrete without fly ash content showed the highest value at 8.84 MPa compared to other mixtures, indicating that the fly ash content exceeded the optimum amount for the mix design. In summary, the concrete mixtures with fly ash displayed several advantages, but their suitability depends on the specific type of construction.

Replacing fly ash with a natural pozzolan in normal strength concrete and ultra-high performance concrete

Fly ash is a widely-used supplementary cementitious material (SCM) in concrete. Common reasons for using fly ash in normal strength concrete (NSC) are to reduce cement consumption and mitigate alkali-silica reaction. Additionally, fly ash is being used in ultra-high performance concrete (UHPC) to reduce use of silica fume which is more expensive than fly ash. Fly ash and silica fume are important SCMs in UHPC that provide a dense microstructure, improving UHPC strength and durability. However, fly ash is becoming less available because the energy industry has been investing in renewable energy production and removing coal burning power plants from operation. Therefore, there is a need to identify sustainable SCMs to replace fly ash in NSC and UHPC mixtures. Natural pozzolans are a diverse class of siliceous or siliceous and aluminous materials that can form compounds possessing cementitious properties in the presence of water. Since natural pozzolans are easily mined, they are usually considered to be more sustainable than Portland cement and nearly as sustainable as other SCMs such as fly ash and silica fume. This experimental study evaluated the effects of a natural pozzolan (pumicite) as a potential replacement for fly ash that can produce comparable rheological and mechanical properties in NSC and UHPC mixtures. Results indicated that workability of both NSC and UHPC mixtures containing pumicite was consistent enough to achieve the targeted workability in just a few trials. Additionally, NSC mixtures with 30% pumicite had comparable compressive strength compared to NSC mixtures with 30% fly ash. Modulus of rupture (MOR) for NSC mixtures containing 30% pumicite (greater than 4.10 MPa) exceeded the MOR for specimens containing 30% fly ash. For UHPC mixtures, results showed that up to 75% of the fly ash in the control mixture could be replaced with pumicite while still producing acceptable compressive and flexural strengths. Based on these results, it appears that pumicite can be a reliable alternative for fly ash in NSC and UHPC mixtures in terms of rheological and mechanical properties.

Roller compacted concrete technology for vehicle parking area solutions

The purpose of the article is presenting the application of the roller compacted concrete (RCC) as alternative solution to asphalt parking places and roads, showing the advantages and further possibilities for development of RCC in wide range of projects. RCC is produced similar to conventional concrete. However, RCC is zero slump concrete unlike conventional concrete. In this study the construction for parking area in RCC technology is presented for the real project. Presented cases concern heavy and light vehicles parking areas. The experimental results shows the very good quality of RCC placed on site, high compressive strength of the concrete, good workability of the concrete mixture that allows for proper placing of the concrete. RCC provides better mechanical-durable properties, more economical and less carbon footprint based on proper compaction and on lower water/cement ratio comparing to conventional concrete. The article draws attention to the role of the soil under the RCC as well, which should be designed and prepared on site with an appropriate stiffness and should be made according to the requirements resulting from the use of RCC. Such a comprehensive implementation of the soil-RCC subbase system guarantees the proper quality, load-bearing capacity and durability of the structure of the parking places as well as roads, for the assumed period of operation.

Characteristics of metakaolin-based geopolymers using bemban fiber additives

<p>The aim of this study was to investigate the chemical composition and thermal properties of kaolin, the physical properties of metakaolin, and the mechanical properties of metakaolin-based geopolymers using bemban fiber. Kaolin was calcinated to become metakaolin at 600 ℃ for 2 h for optimum conditions. The chemical composition of kaolin mostly consisted of 59.30% SiO<sub>2</sub>, 34.30% Al<sub>2</sub>O<sub>3</sub>, and 3.06% Fe<sub>2</sub>O<sub>3</sub>. The transformation of kaolin into metakaolin with temperature was determined through thermal stability tests and analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Regarding the thermal properties of kaolin, predehydroxylation occurred at 31.07–92.69 ℃, dihydroxylation occurred at 400–600 ℃, and the endothermic peak in the DTA curve was recorded at 505.63 ℃. This research also analyzed the physical and mechanical characteristics of metakaolin-based geopolymers, with the additional variation percentages of bemban fiber alloys resulting from a 3% NaOH alkalization treatment for 2 h. The test results indicate that the bemban fiber improves the physical and mechanical characteristics of geopolymers. This improvement is related to the enhanced geopolymer characteristics, including a water absorption capacity of 1.10%, porosity of 2.32%, compressive strength of 35.33 MPa, and splitting tensile strength of 11.29 MPa with the addition of 1.5% bemban fiber. Although the split tensile strength increases as the fiber content increases, adding 1.5% of bemban fiber is optimum because a higher content decreases the workability of mixtures.</p>

High-flowable and high-performance steel fiber reinforced concrete adapted by fly ash and silica fume

The incorporation of steel fibers in concrete imparts strain-hardening characteristics, significantly elevating the tensile toughness of the concrete mixture. However, this enhancement often comes at the expense of reduced workability and strength, posing challenges in achieving optimal densification in practical engineering applications. Moreover, the improvement of the performance of steel fiber-reinforced concrete (SFRC) hinges on the establishment of interfacial transition zone (ITZ) between steel fibers and the concrete paste. It has been established that the introduction of fly ash and silica fume to concrete mixtures can increase fluidity and strength. Consequently, this study investigates the impact of fly ash and silica fume on the performance enhancement and workability of SFRC mixtures, scrutinizing both macroscopic and microscopic aspects. Two sets of high-flowable steel fiber-reinforced concretes (HF-SFRC) incorporating silica fume or fly ash were prepared and subjected to testing. The assessment covered mechanical properties, including compressive strength, compressive toughness, and flexural toughness, along with the microstructure. The microstructure provides evidence that fly ash and silica fume reduced the voids in the concrete matrix to different degrees and that the fully hydrated dense matrix contributed to reinforcing the bond between steel fibers and the cement matrix. The synergistic effect among fly ash or silica fume, steel fibers, and cement in the mixture resulted in enhanced flowability and improved mechanical properties in HF-SFRC.

Synergic Effect of Recycled Carbon Fibers and Microfibrillated Cellulose Gel for Enhancing the Mechanical Properties of Cement-Based Materials.

A new hybrid fiber blend containing microfibrillated cellulose (MFC) gel and recycled carbon short fiber (RCSF) was implemented for designing fiber-reinforced cement mortars, to further improve the mechanical properties and enhance the sustainability of cement-based materials. The individual impact of single fibrous fillers as well as the synergistic effect of a hybrid fiber system (MFC + RCSF) were investigated in terms of the rheological properties, mechanical strength, and microstructure of the mortars. The results indicated that the workability of fresh mixtures slightly increased after fiber addition. The fibers incorporated alone improved the materials' performance in different ways. The addition of RCSF led to improvements of up to 76% in flexural strength and 13% in compression strength for a fiber content of 0.75 wt.%. However, the addition of carbon fibers led to slight deteriorations in terms of porosity and water absorption. On the other hand, the use of MFC induced a less significant growth in terms of mechanical strength (+14% in flexural strength for 0.75 wt.% of cellulose) but greatly improved the microstructural quality of the mortar, significantly reducing its water permeability. Considering the optimum MFC dosage, MFC+RCSF hybrid mixtures showed positive effects on the mechanical properties and microstructure of the mortar, displaying further improvements in strength, while preserving a lower porosity and water absorption than the control mix.

EFFECT ON PROPERTIES OF CONCRETE BY PARTIAL REPLACEMENT OF CEMENT WITH METAKAOLIN AND SUPERPLASTICIZER

Metakaolin, a pozzolanic material, has been recognized for its potential to enhance concrete properties, while superplasticizers are commonly used to improve workability and reduce water content in concrete mixtures. The experimental program involves the preparation of concrete mixtures with metakaolin replacements at different levels (by 0%, 5%, 10%, 15%, and 20% by weight of cement). A commercially available superplasticizer is added to the mixtures (by 0%, 0.5%, 1%, 1.5%, and 2% by weight of cement) to optimize workability. The properties of the resulting concrete, including slump cone test, compressive strength, flexural strength, split tensile strength are assessed. The results show that the incorporation of metakaolin in concrete leads to improved mechanical properties, with significant enhancements observed in compressive and flexural strengths. Moreover, the inclusion of a superplasticizer improves the workability of the concrete mixtures containing metakaolin, ensuring easier placement and compaction. Key Words: Concrete, Metakaolin, Superplasticizers.

Enhancing Reinforced Concrete Beams: Investigating Steel Dust as a Cement Substitute

This research undertook an extensive examination of the ramifications of integrating steel dust as a partial substitute for cement within reinforced concrete beams. The investigation encompassed an assessment of various facets, encompassing the workability of the concrete mixture, alongside crucial mechanical properties such as compressive strength, split tensile strength, flexural strength, ultrasonic pulse velocity (UPV), and elasticity modulus. The findings unveiled a notable reduction in workability as the proportion of steel dust increased within the mixture, with a consequential substantial impact on the elasticity modulus. Notably, compressive strength exhibited an enhancement at a 10% replacement of cement yet exhibited a decline with higher degrees of cement substitution. The inclusion of steel dust led to the formulation of adjusted equations pertaining to split tensile and flexural strength characteristics within the mixture. Remarkably, the incorporation of 10% steel dust yielded an increase in ductility. Conversely, at a 30% steel dust inclusion level, ductility diminished alongside a reduction in the maximum load-bearing capacity. In light of these findings, it is imperative to exercise prudence when considering the utilization of steel dust as a cement substitute, particularly when approaching or exceeding the 10% replacement level threshold. Further comprehensive research is imperative to acquire a comprehensive understanding of its implications and its susceptibility to potential corrosion concerns.

Analisis Indeks Workabilitas pada Campuran Asphalt Concrete dengan Asbuton B 50/30

The majority of road construction in Indonesia uses flexible pavement, namely Asphalt Concrete (AC). Therefore, to meet the need for asphalt, Asbuton was carried out. This research aims to determine the effect of Asbuton content, mixing temperature, and compaction temperature on the workability index value. Therefore, research was carried out regarding the workability of the AC-WC mixture with Asbuton B 50/30
 The preparation of test objects was carried out using the dry mixing method. The Asbuton content used was 10% and 15% and the mixing temperature was varied, namely 160⁰ C, 170⁰ C, 180⁰ C 190⁰ C, and 200⁰ C and the compaction temperature was 110⁰ C, 120⁰ C, 130⁰ C, 140⁰ C, and 150⁰ C at the level optimum asphalt. Then, the data obtained is processed using a statistical approach.
 The research results showed that the AC-WC mixture with 10% Asbuton content and varying mixing and compaction temperatures had a workability index value from 2.9890 to 5.7737. Meanwhile, the AC-WC mixture with 15% Asbuton content and varying mixing and compaction temperatures has a workability index value ranging from 3.3252 to 6.9845. This shows that variations in Asbuton content, mixing temperature and compaction temperature influence the workability index value of the AC-WC mixture.

Performance-related methods for the characterization of cold mix patching materials used in asphalt pavements maintenance

Cold mix patching materials (CMPMs) are commonly used as an alternative to hot mix asphalt (HMA) for repairing road pavement potholes, especially in cold and wet seasons. Currently, the acceptance criteria and expectations for the mechanical strength and durability of CMPMs are often compared or related to those adopted for traditional HMA pavements without considering the specific performance characteristics of CMPMs required to ensure their effectiveness. In response to this, the authors proposed innovative solutions derived from pre-existing methodologies to evaluate CMPMs. Several parameters, indicative of CMPMs' structural and functional performance, were measured to optimize the mix design and systematize the quality assurance/quality control (QA/QC) process at various service life stages and under different boundary conditions. Besides the standard Marshall stability and indirect tensile strength (ITS), which were chosen as references, Hubbard-Field and indentation stability tests were reintroduced, suggesting modified procedures specifically tailored to CMPM stability evaluation. Similarly, brush, Leutner, and locking point test methods were customized for analyzing the raveling potential, bonding properties, and workability of the patching materials. The research outcome showed that Hubbard-Field and indentation stability tests provided more accurate stability assessments, even for materials unsuitable for testing using Marshall stability and ITS methods. Modified brush and Leutner tests effectively replicated real-world conditions, enhancing the relevance of laboratory findings to practical applications. Furthermore, the locking point method enabled mixture workability classification. These findings contribute to a better understanding of CMPM performance and can inform more targeted and effective road repair strategies.

Assessment of the rheological and mechanical properties of palmyra fruit mesocarp fibre reinforced eco-friendly concrete

Concrete's poor tensile strength has led to the extensive use of artificial fibre reinforcements throughout history. However, the environmental impacts associated with the production of these fibres have raised concerns, spurring interest in sustainable alternatives, including natural fibres. The untreated fibre extracted from the mesocarp region of full-grown palmyra fruit is a promising natural substitute. This study investigates the effects of adding palmyra fibre (PF) into concrete as a partial replacement for cement. Four fibre concentration levels of 0.5%, 1%, 1.5%, and 2% were considered without any fibre treatment. The addition of PF decreased the workability of fresh concrete mixtures, but it improved compressive strength by 10% and split tensile strength by 21% at an optimal PF concentration of 1%. Higher fibre concentrations led to lower mechanical strength but increased ductility as the compression-to-tension ratio was increased by 35% with incorporation of 2% fibre. Furthermore, fibre-reinforced concrete mixtures had lower production costs and carbon dioxide emissions than conventional concrete mixtures. Overall, this study suggests that palmyra fibre has significant potential for producing sustainable concrete structures.

Novel application of potassium methylsiliconate in cement-based materials: Retarding of hydration process and improvement of compressive strength

The presented research investigates the application of the organosilicon compound named potassium methylsiliconate (MESI) as a set-retarding admixture for cement-based materials which also provides the strengthening effect. The study concerns the impact of three dosages of MESI (1%, 2% and 3% per cement mass) on the properties of the cement paste, mortar and concrete. The greatest delay of the setting time of cement CEM I 42.5 R and retardation effect, examined by manual Vicat apparatus, was observed for addition of 1% methylsiliconate. The beginning of the setting was prolonged to 23 h. The influence of potassium methylsiliconate on the kinetics of cement hydration was investigated by isothermal calorimetry. The calorimetric results disclosed significant extension of induction period during Portland cement hydration with addition of potassium methylsiliconate as an admixture. It is especially visible in case of addition of 1% of MESI. Moreover, tests performed at 30 °C, 40 °C and 50 °C showed that MESI can also delay the cement hydration at higher temperatures. The influence of potassium methylsiliconate on the compressive strength of cement mortar and concrete after 1, 2, 7, 28 days and72 days was also investigated. In the first days of hydration, the compressive strength of the materials was reduced, but after 28 days of curing the compressive strength was increased by 21% and 16% for cement mortar and concrete, respectively. The impact of MESI on the microstructure and pore size distribution of cement pastes in 2nd, 7th and 28th of hydration was examined by mercury intrusion porosimetry (MIP). The result showed significant delay in the development of the cement pastes microstructure during the first days of hydration. The XRD and DTA/TG analysis provided the knowledge about impact of siliconate on the composition and formation of the cement phases. Both, the XRD and DTGA/TG analyze showed noticeable changes in portlandite formation during the first days of hydration. The conducted research and obtained results reveal the innovative and novel application of potassium methylsiliconate as retarders, which prolongs the workability of fresh mixture and improves the compressive strength of matured concrete and mortar. This admixtures can be a competitive alternative to traditional retarders.

Enhancing workability and sustainability of asphalt mixtures: Investigating the performance of beeswax as a novel additive for warm mix asphalt

Asphalt, a crucial road component, demands ongoing research for better performance and environmental impact reduction. This study explores how adding beeswax as an asphalt binder modifier affects mixture properties. Binders were enhanced with three beeswax concentrations (1%, 3%, and 5%), followed by thorough testing covering temperature, rheological traits, and performance factors. Statistical analyses were used to interpret results. Findings reveal lower mixing and compaction temperatures due to beeswax. Specifically, 1%, 3%, and 5% beeswax lowered temperatures by 2 °C and 1 °C, 4 °C and 4 °C, and 9 °C and 12 °C during mixing and compaction. Mixtures with 3% and 5% beeswax improved resilient modulus but showed reduced resistance to permanent deformation and moisture damage. These mixtures could suit low-traffic roads and regions with little rainfall, like northeastern Brazil and North African countries. Adding beeswax aligns with eco-friendly construction, offering benefits like lower temps, energy savings, and fewer emissions. The use of beeswax introduces an intriguing concept, merging culinary and construction worlds, highlighting its potential use from various perspectives.

A study on improving the performance of cement-based mortar with silica fume, metakaolin, and coconut fibers

Cement mortar is the primary choice for construction due to its widespread usage. However, certain applications demand high-performance cement mortar. In this pioneering study, we explore using agriculture waste products, industrial by-products, and naturally occurring kaolinite clay as potential additives in composite cement. Our research aims to assess these materials' physical and mechanical attributes to ascertain their efficacy in elevating cement performance. To achieve this, we replaced 20% of the cement in the composite with silica-fume and metakaolin, following a precise mix design fraction of 1:1 (binding materials: sand) for the mortar composites. We successfully identified the optimum combination of metakaolin and silica fume through systematic experimentation that maximizes compression strength. Subsequently, we introduced various proportions of coir fibers (ranging from 3% to 15% by weight) into the cement composite to enhance its structural support capabilities. We carefully calibrated the ratio of the water-to-binding material (ranging from 0.35 to 0.6) to maintain the workability of the cement mixtures. Next, we subjected the cement composites to meticulous curing in water for 7 days, 14 days, and 28 days, respectively, to observe their performance over time. Our comprehensive study encompassed the investigation of critical parameters, including moisture content, density, and water absorption, as well as essential mechanical properties such as compressive strength and modulus of rupture. A total of 270 specimens underwent rigorous testing, yielding compelling results. The composite featuring a combination of 10% silica fume, 10% metakaolin, and 6% coconut fibers showcased superior mechanical and physical properties. SEM and EDX studies also showed dense and packed microstructure of mortar samples. These findings showcase the remarkable potential of this specific composite composition as an environmentally conscious and sustainable alternative to enhance cement performance in construction applications. This research advances eco-friendly construction practices by harnessing the strength of waste-derived materials and naturally occurring resources, supporting a more sustainable and resilient approach to infrastructure development.

Influence of Graphene oxide on abrasion resistance and strength of concrete

Graphene Oxide (GO) has recently gained significant attention as a new carbon-based nanomaterial (CBN) in the civil engineering industry due to its exceptional mechanical and functional properties. It has been increasingly gaining popularity due to its superior dispersibility characteristics in aqueous solutions compared to the other graphene-based derivatives due to attached oxygen functional groups. A majority of current studies are focused on investigating the effect of GO in cement composites. However, the more useful applications of GO lie in its incorporation into concrete, as it is the most widely used construction material. Therefore, the current study determines the performance of GO-incorporated concrete in terms of strength and abrasion characteristics. Industrially produced GO was added to the concrete mixes at percentages varying from 0.02% to 0.08% by weight of cement (bwoc). A polycarboxylate-ether-based superplasticiser (PS) was used to enhance the dispersibility of GO within the mix and the workability of concrete mixtures. The Standard slump tests were performed to evaluate the workability of the mixes. Compression and indirect tensile strength tests were conducted to obtain the mechanical properties, while abrasion tests were employed to investigate the durability properties. In addition, microstructural properties were obtained using scanning electron microscope (SEM) analysis. The test results show that adding 0.08% GO bwoc in the concrete mix enhanced its compressive strength, indirect tensile strength, and abrasion resistance by 21%, 12% and 23% at 28 days compared to the control mix. At 56 days, results show 19%, 12% and 20% improvements, respectively. These findings confirmed that adding GO can enhance concrete's abrasion resistance and mechanical properties. Therefore, it demonstrates promising outcomes of utilising GO in applications such as road pavements, airport runways, industrial floorings and bridge decks where abrasion resistance and strength are key design parameters.

Geometrical characteristics of aggregates: The influence of sphericity, angularity, and surface texture on the workability of asphalt mixtures

Workability of asphalt mixtures is considered as an essential factor in quality control of asphalt pavement construction. However, there are fewer studies related to the influence of geometric properties of aggregates on the workability of asphalt mixture. The main purpose of this paper is to explore the influence of aggregate sphericity, angularity and surface texture on the workability of asphalt mixture during the mixing process. Firstly, a self-developed workability equipment of asphalt mixture was used to analyze the differences in the asphalt mixture workability of three materials, namely, basalt, limestone and pebble. Next, using the Aggregate Image Measurement System (AIMS), the geometric characteristics of the aggregates were determined. Accordingly, the correlation between the geometric characteristics of the aggregates and the workability index was established through linear correlation analysis. Finally, investigating the distribution uniformity of asphalt film by scanning electron microscope (SEM), the influence of the geometric characteristics of the aggregates on the workability of the asphalt mixture was determined. The results demonstrated that, compared with limestone and pebble asphalt mixtures, a significantly greater workability value was observed for the basalt asphalt mixture. Moreover, the geometric characteristics of the aggregates were found to influence the change rule of workability in the following order: sphericity > surface texture > angularity. Furthermore, the geometric characteristics revealed to have a significant effect on the uniformity of the asphalt film.

Determination of optimum blast furnace slag ash and hemp fiber ratio in cement mortars

This study aims to investigate the effect of incorporating hemp fibers into cement mortars to enhance their mechanical properties. Additionally, the study examines the use of blast furnace slag (YFC) as a substitute for cement to reduce costs. The findings demonstrate that adding 1%, 2%, and 4% hemp fibers to cement mortars yields the best results in terms of density, water absorption, compressive strength, bending strength, compressive strength after bending, and flexural strength. In conclusion, the study reveals that incorporating hemp fibers enhances the workability of YFC-blended mixtures while reducing the spreading diameter as the hemp fiber content increases. Additionally, an increase in YFC substitution leads to a decrease in compressive strength; however, the addition of 1% hemp fiber to the Y15 mixture results in a approximately 12% increase in compressive strength, indicating improved matrix strength and reduced crack formation. Moreover, the study shows that the flexural strength increases with the addition of hemp fibers, with the highest flexural strength observed in the mixture containing 4% hemp fiber and 10% YFC substitution. The results highlight that the combination of YFC and hemp fibers can produce strong, durable, and environmentally friendly composite materials. These materials offer a lower environmental impact and cost-effectiveness compared to traditional construction materials.