High-performance Self-consolidating Concrete Research Articles

SHRINKAGE MITIGATING STRATEGIES ON HIGH-PERFORMANCE SELF-CONSOLIDATING CONCRETE (HP-SCC)

Cracking in high-performance self-consolidating concrete (HP-SCC) is a significant concern that must be addressed during design and construction. HP-SCC is a concrete type reinforced with high-strength fibers, such as steel or synthetic fibers, to enhance its mechanical properties. HP-SCC is known for its high flowability and ability to self-consolidate without vibration, exceptional strength, durability, and crack resistance compared to conventional concrete. HP-SCC is highly durable and can withstand various environmental conditions and aggressive exposures. Combining high-strength fibers and advanced cementitious materials in HP-SCC improves resistance to chemical attacks, freeze-thaw cycles, abrasion, and impact. Utilizing an expansive agent (EA), shrinkage-reducing admixture (SRA), and saturated lightweight sand (LWS) ensures HP-SCC with a low risk of cracking. This study investigates using different types of EAs to improve compressive and flexural properties. Furthermore, the study investigates the combination of fiber, EA, and LWS in promoting high resistance to autogenous and total shrinkage. The dense microstructure of HP-SCC also contributes to its durability by reducing permeability and minimizing the ingress of moisture and harmful substances.

Approximation of elasticity modulus of groundnut shell ash-based self-consolidating high-performance concrete using artificial neural network

Approximation of elasticity modulus of groundnut shell ash-based self-consolidating high-performance concrete using artificial neural network

Effect of Utilisation of Nano POFA on Performance of Self-Consolidating High-Performance Concrete (SCHPC)

Malaysia's palm oil industry plays a significant role in the country's economy. However, a large amount of palm oil fuel ash (POFA), a by-product of this industry, may negatively affect the environment and human health. Hence, this study hypothesized that POFA might be re-used in the form of replacement in concrete to lessen the risk to the environment or human health. Self-consolidating high-performance concrete (SCHPC) has been innovating progressively over the years. In this paper, SCHPC is innovated by utilising nano POFA (NaPOFA) to improve its performance. The POFA performance greatly improved when the particle size is reduced because the finer forms of POFA react effectively with the other constituent materials to produce stronger concrete. Hence this paper presents the experiment of the effect of utilisation of NaPOFA as a replacement to cement ranging between 0% and 10% to produce a self-consolidating high-performance concrete with good workability. The tests conducted were the flow table and compression test. The specimen used in the compression tests were 50 mm concrete cubes, tested in 1, 3, 7, 14, and 28 days. It was found that the inclusion of 1% POFA as a replacement to cement in concrete produced the highest compressive strength, 73.31 MPa, on the 28th day of testing. It was also found that its workability was as good as the control concrete. Thus, the utilisation of POFA could be considered environmental-friendly since it can be used as cement replacement and enhance the performance in terms of workability and strength.

Assessment of High Performance Self-Consolidating Concrete through an Experimental and Analytical Multi-Parameter Approach.

High-performance self-consolidating concrete is one of the most promising developments in the construction industry. Nowadays, concrete designers and ready-mix companies are seeking optimum concrete in terms of environmental impact, cost, mechanical performance, as well as fresh-state properties. This can be achieved by considering the mentioned parameters simultaneously; typically, by integrating conventional concrete systems with different types of high-performance waste mineral admixtures (i.e., micro-silica and fly ash) and ultra-high range plasticizers. In this study, fresh-state properties (slump, flow, restricted flow), hardened-state properties (density, water absorption by immersion, compressive strength, splitting tensile strength, flexural strength, stress-strain relationship, modulus of elasticity, oven heating test, fire-resistance, and freeze-thaw cycles), and cost of high-performance self-consolidating concrete (HPSCC) prepared with waste mineral admixtures, were examined and compared with three different reference mixes, including normal strength-vibrated concrete (NSVC), high-strength self-compacted concrete (HSSCC), and high-performance highly-viscous concrete (HPVC). Then, a multi parameter analytical approach was considered to identify the optimum concrete mix in terms of cost, workability, strength, and durability.

Effect of microlimestone on properties of self-consolidating concrete with manufactured sand and mineral admixture

Self-consolidating concrete (SCC) with manufactured sand (MSCC) is crucial to guarantee the quality of concrete construction technology and the associated property. The properties of MSCC with different microlimestone powder (MLS) replacements of retreated manufactured sand (TMsand) are investigated in this study. The result indicates that high-performance SCC, made using TMsand (TMSCC), achieved high workability, good mechanical properties, and durability by optimizing MLS content and adding fly ash and silica fume. In particular, the TMSCC with 12% MLS content exhibits the best workability, and the TMSCC with 4% MLS content has the highest strength in the late age, which is even better than that of SCC made with the river sand (Rsand). Though MLS content slightly affects the hydration reaction of cement and mainly plays a role in the nucleation process in concrete structures compared to silica fume and fly ash, increasing MLS content can evidently have a significant impact on the early age hydration progress. TMsand with MLS content ranging from 8% to 12% may be a suitable alternative for the Rsand used in the SCC as fine aggregate. The obtained results can be used to promote the application of SCC made with manufactured sand and mineral admixtures for concrete-based infrastructure.

The influence of type and combination of polycarboxylate ether superplasticizer on the mechanical properties and microstructure of slag-silica fume ternary blended self-consolidating concrete

It is a common practice to blend various kinds of chemical admixtures during concrete fabrication in order to achieve desired properties of concretes. Nevertheless, there were limited experimental works reported on the influence of such activity on the properties of the concrete composite, particularly along with the blended cement concrete. Therefore, an experimental investigation was conducted to examine the effects of the type and combination of polycarboxylate-based (PCE) superplasticizer with different chemical structures on the properties of the high performance self-consolidating concrete (HPSCC) utilizing supplementary cementitious materials such as Ground Granulated Blast Furnace Slag (GGBS) and Densified Silica Fume (DSF). The drying shrinkage and mechanical performances in terms of mechanical strength, bulk density of the HPSCC were evaluated. Also, the influences of PCE on the morphology of hydrate products and the microstructure development of HPSCC were examined with the aid of the Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) technique. The results showed that the use of methoxy polyethylene glycols (MPEG) and isoprenyl polyethylene glycols (TPEG) PCE as a single chemical has a similar beneficial effect on most of the mechanical properties of the HPSCC, but increasing the drying shrinkage strain. On the other hand, the use of blended MPEG and TPEG PCE imposes an opposite effect on the mechanical properties and the drying shrinkage of the HPSCC compared to another two PCE series. This was due to the formation of both foil-like and fibril-like C–S–H bonds that weakens the C–S–H network's strength in the microstructure of concrete with such combination of PCE. Thus, the combination use of different types of PCE superplasticizers in the production of HPSCC was not encouraged due to the adverse results observed in terms of mechanical properties of concretes.

Combined use of untreated-waste rice husk ash and foundry sand waste in high-performance self-consolidating concrete

High-performance self-consolidating concrete (SCC) has great potential for advanced applications in modern concrete construction. SCC has high-performance characteristics especially high flow when in its fluid state it is poured into complicated molds and passes congested reinforcing steel without either excessive segregation or bleeding. Thus, SCC can develop strong early- and long-term mechanical and durability properties. The focus of this study is the combined effects of using foundry sand waste (FDW) obtained from the process of casting automobile engine parts as a fine aggregate replacement for Type-I Portland cement (OPC) in the amounts of 30 and 50 wt% with untreated rice husk ash (RHA) obtained from a rice husk–based fuel electricity power plant to replace OPC in the amounts of 10 and 20 wt%. The SCC prepared with water-binder materials (OPC and/or RHA) at a ratio (w/b) of 0.35 and 0.45 and the targeted slump flow in SCC production (the measured slump flow must be in the range of 70.0 ± 2.5 cm. In this study, a comprehensive investigation is undertaken that includes tests to determine the SCC specimens' fresh, hardened, and durability properties. The results indicate that FDW used to replace OPC to the extent specified has a positive effect on the SCC with RHA, increases the required superplasticizer amount and setting times compared to those of the control SCC, and decreases the slump flow of SCC. The incorporation of RHA and FDW decreases the filling, passing ability, and segregation of SCC while increasing its durability. In summary, with 10 wt% RHA together with 30 wt% FDW, the RHA-FDW-SCC produced showed the highest compressive and splitting tensile strengths of all the specimens tested compared to conventional SCC and met the durability requirements for SCC.

Ternary blended cement: An eco-friendly alternative to improve resistivity of high-performance self-consolidating concrete against elevated temperature

The unique fresh and hardened properties of high-performance self-consolidating concrete (HPSCC) led to an extensive application of this mixture in high-rise buildings. In this paper, the elevated temperature resistivity of 19 HPSCC mixtures incorporating binary and ternary blends of fly ash, silica fume, natural zeolite, and metakaolin was investigated. Changes in mass, compressive strength and ultrasonic pulse velocity (UPV) of the mixtures were measured at different temperatures (20, 300, 500, and 700 °C). A life cycle assessment (LCA) was also employed to explore the environmental performance of the mixtures. The test results revealed that in ambient temperature, ternary mixtures incorporating natural zeolite and fly ash or natural zeolite and metakaolin have lower compressive strength than that of the control mixture. The residual compressive strengths of fly ash-silica fume-incorporated mixture was similar to those in binary mixtures. The UPV test results revealed a larger than 50% reduction in transition velocity when the temperature was above 500 °C, and there is a strong association between the UPV and compressive strength test results of the mixtures at different temperatures, but the correlation decreased inversely proportional to the exposure temperature. Among the ternary mixtures, those mixtures that incorporate natural zeolite indicate the most significant mass loss after exposing to elevated temperature. The environmental results indicate that the substitution of pozzolanic materials with Portland cement may not always be beneficial. The ecosystem quality results of binary fly ash mixtures were larger than the control mixture due to the extensive transportation distance of import. In addition, metakaolin binary mixture exposes larger damage to the resources. Silica fume-incorporated mixtures had significant damage to human health. The ternary blended mixtures can be a remedy to obtain the optimized fire-resistant results and to compensate the environmental burdens of the inferior pozzolan in all the damage categories.

Short term durability study of groundnut shell ash blended self consolidating high performance concrete in sulphate and acid environments

Groundnut shell ash (GSA) has been used in concrete production by various authors as supplementary cementitious materials with limited utilization for self-consolidating concrete. For this reason, investigation of effect of groundnut shell ash on strength properties of self-consolidating high performance concrete (SCHPC) in sulphate and acid environment at high substitution level of 40% by total weight of binder was conducted. The principal characteristics measured were fresh properties (filling ability, passing ability and segregation resistance) and compressive strength of ordinary Portland cement OPC/GSA concrete at varying substitution level (0%, 10%, 20%, 30%, 40%) after curing in water and in three different chemical solutions (CaSO4, MgSO4 and H2SO4) of 5% concentration each at 7, 14, 28 days hydration period. The designed mix of 40Mpa maximum strength target was used to produce a total of 225 cube size of 100 × 100 × 100 mm. The investigations revealed significantly improved fresh and hardened properties as well as durability of the developed SCHPC at 10% GSA substitution level as compared to that of the control concrete mix. Conclusively, GSA is a suitable SCM and can be substituted up to 30% cement replacement to produce SCHPC with improved engineering properties in an aggressive environment.

Assessment of the Changes in Compressive Strength of Deep Beam Elements Using High Performance Self-Consolidating Concrete from a Single Casting Point

This experimental work investigates into the effect of a change in the compressive strength of concrete along the length and height of monolithic deep beams made of high performance self-compacting concrete (HPSCC). In the tests, three different HPSCC mixes were used in which the amount of silica fume differed (0, 5 and 10% by mass of cement). The binder content (550 kg/m3) and the water-binder ratio (0.32) were the same. Experimental deep beams, measuring 1.50 m in length, 0.15 m in width and 0.45 m in height, were cast. A variant of casting was explored in which concrete is cast from the top of a mould from a single casting point at one edge of an element. All the HPSCC mixtures exhibited small variations in the compressive strength in relation to the length and height of the experimental deep beams. In general, those variations were limited to 8% and 16%, respectively. Casting HPSCC from a single casting point at one edge of an element may be used in practice as an alternative way of laying self-compacting concrete.

AN EVALUATION OF THE RELATIONSHIP BETWEEN FRESH PROPERTIES OF SELF-CONSOLIDATING CONCRETE INCORPORATING BLENDED PALM OIL FUEL ASH AND PULVERISED BURNT CLAY

Although the application of palm oil fuel ash and pulverised burnt clay in selfconsolidating concrete is gaining prominence, their application singly in binary mixes is associated with some setbacks. In this study, a blend of Palm oil fuel ash (POFA) and pulverised burnt clay (PBC) was used as partial replacement of Ordinary Portland cement (OPC) to produce self-consolidating high performance concrete (SCHPC). Fifteen different mixes were prepared with varying percentages of blended POFA/PBC, high range water reducing admixture (HRWR) and water to binder ratio (W/B) ranging from 0.30-0.40. Three key fresh properties were investigated. The filling ability was evaluated based on the slump flow, 500mm slump flow time (T500), inverted slump cone flow spread and time, Orimet flow time and v-funnel flow time. The passing ability was evaluated with respect to J-ring flow and L-box blocking ratio. Furthermore, the segregation resistance was determined based on the sieve segregation index and column segregation factor. A comparative analysis was carried out on the results based on the correlations established among the fresh properties of the respective mixes. The research findings revealed strong correlations between most of the fresh properties of the respective SCHPC

Properties of SCC prepared using natural pozzolana and industrial wastes as mineral fillers

The high unit cost of self-consolidating concrete (SCC) resulting from the use of conventional filler materials, such as fly ash or silica fume, has been identified as the main hindrance to its widespread use particularly at places where these materials are not available locally. To achieve economy in the production of SCC, it is highly desirable to explore possibility of using alternative materials as mineral fillers through the evaluation of technical and economic benefits of SCC made with these materials. This paper presents the results of a study conducted to evaluate the performance of ternary SCC mixtures prepared using some industrial wastes as mineral fillers which include limestone powder, cement kiln dust, bag house dust, pulverized steel slag and metakaolin, each in conjunction with natural pozzolana. The mechanical properties and durability characteristics of the SCC mixtures satisfying the requirements of self-compactability at optimally selected dosages of chemical admixtures were evaluated. Except the SCC mixture incorporating bag house dust, the early and later-age strengths of the other SCC mixtures were found to be very high. Further, the good corrosion resistance exhibited by the developed SCC mixtures showed that the high performance SCC mixtures can be prepared utilizing these industrial wastes as mineral fillers.

Optimizing the durability and service life of self-consolidating concrete containing metakaolin using statistical analysis

This paper utilizes the statistical design of experiments approach to optimize the mixture design of self-consolidating concrete (SCC) incorporating metakaolin (MK). The factors studied were total binder content, percentage of MK, water-to-binder ratio, and curing conditions. The results obtained from the developed statistical models were exploited to determine the most significant factors affecting the chloride permeability and the expected service life (calculated using Fick’s second law of diffusion) of the tested mixtures. The developed models were also used to optimize the level of each response variable to minimize the chloride permeability, and to maximize the expected service life of the developed high performance SCC mixture. The results yielded an optimum SCC mixture with MK which achieved the lowest chloride permeability compared to counterpart SCC mixtures containing fly ash, slag, and silica fume. The results also showed that MK replacement proved to be the most significant variable affecting the chloride permeability, decline of permeability over time, and the service life of the tested mixtures.

Properties of self-consolidating concrete made utilizing alternative mineral fillers

Self-consolidating concrete (SCC) is a concrete material possessing an ability to take formwork shapes and pass through congested reinforcement bars without being vibrated, making it a ‘smart concrete’ material. However, the high cost of SCC resulting from the use of mineral fillers and high cement content has been a main factor impeding the widespread use of this smart material. Consequently, there is a need to investigate the use of low cost materials in the production of SCC to ensure adoptability of SCC in concrete construction. This paper presents the results of a study conducted to develop and evaluate the performance of four SCC mixtures using different combinations of filler materials, such as silica fume, natural pozzolana and metakaolin, in conjunction with limestone powder. The developed SCC mixtures exhibited high strength (compressive, tensile, bond and elastic modulus), excellent shrinkage behavior and good durability characteristics (high corrosion resistance and related indices). The findings of this study indicated the possibility of producing cost-effective and high-performance SCC mixtures using the mineral fillers considered in this study.

Mechanical and durability properties of self consolidating high performance concrete incorporating natural zeolite, silica fume and fly ash

Mineral admixtures are widely used as cement replacement materials in both high performance concrete (HPC) and self consolidating concrete (SCC). While the effect of mineral admixtures on rheological properties of SCC and mechanical behavior of HPC has been investigated by many researchers, further research is needed to optimize the effective dosage of these admixtures in self consolidating high performance concrete (SCHPC). Moreover, the effects of some mineral admixtures such as natural zeolite on properties of SCHPC has not been well established yet. This paper discusses the effect of natural zeolite, silica fume and fly ash on the properties of fresh and hardened concrete. Slump flow, superplasticizer demand, compressive strength, electrical resistivity, water absorption and chloride permeability were measured for all mixes. The test results indicate that incorporation of mineral admixtures generally improve mechanical and durability characteristics of the mixes. However, silica fume is slightly more effective than natural zeolite or fly ash in improving durability properties of SCHPCs, while natural zeolite is much more cost effective.

Properties of Self-Consolidating Concrete Made with High Volumes of Supplementary Cementitious Materials

This paper presents an extensive experimental study to develop a high-performance self-consolidating concrete containing high volumes of supplementary cementitious materials. A total of 20 concrete mixtures were developed and tested. Mixtures were designed to have up to 70% of portland cement replaced by cementitious materials such as class C and class F fly ash, slag, and silica fume. The properties of fresh concrete mixtures such as flowability, deformability, filling capacity, air content, and resistance to segregation were evaluated. Other properties such as permeability, unrestrained shrinkage, tensile strength, and compressive strength at various ages were also investigated. A critical analysis of the results obtained shows that a high-performance self-consolidating concrete can be developed using binary, ternary, or quaternary binders with up to 70% of cement replaced by fly ash, slag, and/or silica fume. Properties of such concrete mixtures are similar and sometimes superior to those of the control mixture made with 100% portland cement.

Hardened properties of self-consolidating high performance concrete including rice husk ash

This paper mainly presents the key hardened properties of self-consolidating high performance concrete (SCHPC). Various SCHPCs were produced with different water/binder (W/B) ratios, rice husk ash (RHA) contents, and air contents. The required filling ability and air content were achieved in all freshly mixed SCHPCs. The hardened SCHPCs were tested for compressive strength, ultrasonic pulse velocity, water absorption, total porosity, and true electrical resistivity. The effects of W/B ratio, RHA content, and air content on these hardened properties were observed. Test results revealed that the compressive strength, ultrasonic pulse velocity, and electrical resistivity increased whereas the water absorption and total porosity decreased with lower W/B ratio and higher RHA content. In addition, the air content decreased the compressive strength, ultrasonic pulse velocity, water absorption, and total porosity but increased the electrical resistivity. Based on the overall effects of rice husk ash, the optimum RHA content for SCHPC has been defined.

Investigation on Toughness of Fibre Cocktail Reinforced Self Consolidating Concrete after High Temperature

The effect of different fibres on the residual load-bearing capacity and the failure pattern of high-performance self consolidating concrete (HPSCC) after exposure to high temperature hass been studied in this work. The polypropylene fibers mitigate the spalling of HPSCC element clearly, but did not show clear effect on the mechanic properties of concrete. The macro steel fiber reinforced HPSCC showed higher flexural toughness and ultimate load before and after high temperatures. The mechanical properties of hybrid fibre reinforced HPSCC (HFHPSCC) after heating were better than that of mono-fibre reinforced HPSCC. The failure mode changed from pull-out of steel fibers at lower temperature to broken down of steel fibers at higher temperature. The use of hybrid fibre can be effective in providing the residual strength and failure pattern, and improving the toughness of HPSCC after high temperature.