Sustainable Ultra-high Performance Concrete Research Articles

RETRACTED: Influence of eco-friendly fine aggregate on macroscopic properties, microstructure and durability of ultra-high performance concrete: A review

Ultra-high performance concrete (UHPC) is considered one of the promising future building material due to its excellent performance. However, it is important to note that the production of quartz sand, the fine aggregate of traditional UHPC, causes several environmental issues, including dust and noise pollution. In addition, excessive use of river sand as a raw material causes a sharp decrease in reserves. Thus, using river sand to prepare UHPC is not a sustainable method. Considering all these undesired impacts, it becomes a necessity for UHPC to meet the increasing demands of environmental sustainability. Another major issue confronting the world is waste disposal. Numerous studies show the feasibility of using industrial by-products, municipal solid waste, and recycled materials as fine aggregates for UHPC. The current work focuses on developing environmentally friendly UHPC using waste instead of quartz sand or river sand. The macroscopic (workability, compressive strength, flexural strength, elastic modulus and shrinkage), microstructural (pore structure, interfacial transition zone), and durability properties of eco-friendly UHPC were comprehensively reviewed. This paper aims to promote the utilization of waste to produce sustainable UHPC and the large-scale use of UHPC worldwide. This development will significantly reduce waste in landfill and decrease the environmental burden of conventional UHPC.

Mechanical and durability performance of ultra-high-performance concrete incorporating SCMs

Production of ultra-high performance concrete (UHPC) requires a high volume of micro silica (MS), called silica fume, that accounts for around 20% to 40% by weight of cement. Using large quantity of MS can impede the use of UHPC in the market due to its high cost and limited resources. This paper evaluates the possibility of producing sustainable UHPC utilizing Supplementary cementitious materials (SCMs) such as Metakaolin (MK), Fly Ash (FA) and Natural Pozzolan (NP) as a partial replacement of MS. The mechanical characteristics such as compressive strength, flexural strength, and fracture toughness and durability performance such as chloride penetrability, water permeability, drying shrinkage, water absorption, electrical resistivity and sulfate resistance were investigated. The results exhibited that a partial replacement of MS with 60% NP, 60% FA and 40% of MK contributed the paramount UHPC mixtures, with satisfactory strength and flowability requirements. The outcomes indicate that the increase in ultra-fine dosages decreases the flowability and increases the strength, as the finer particles perform as a filler between the cement and coarser grains. The UHPC specimens containing FA provided the worthiest results in comparison to other specimens. This study outcome also indicated that the SCMs can be used to develop UHPC with significant improvements in the mechanical and durability performance in comparison with conventional UHPC.

Recent trends in ultra-high performance concrete (UHPC): Current status, challenges, and future prospects

• UHPC is promptly developing as a leading concrete material for construction industries. • UHPC has exceptional properties, making it a potential functional solution for a sustainable construction. • This article scientifically reviews the carbon capturing, challenges, limitations, and applications of UHPC. • The findings of this review likely to help specialists in establishing the design guidelines for sustainable UHPC. • Further efforts are required to standardize testing characterization for the materials used in UHPC. Ultra-high performance concrete (UHPC) combines advanced fibrous and cementitious material technologies to achieve high strength and exceptional durability. The material tends to have microscopic pores that prevent harmful substances such as water, gas, and chlorides from entering. UHPC can also achieve compressive strengths above 200 MPa and tensile strengths above 20 MPa. It also shows significant tensile strain hardening and softening behavior. Owing to all these characteristics, UHPC has excellent performance, making it a potentially attractive solution for improving the sustainability of construction components. Despite UHPC’s outstanding mechanical properties, superior toughness and ductility, and extraordinary durability, various challenges prevent its widespread use. At the same time, several challenges are currently being faced in the applications of UHPC, which include i) design aspects such as material properties; ii) production technology for large-volume and/or long-span elements with low workability, high spalling, and high shrinkage strains; and iii) unknown durability characteristics after the appearance of long-term concrete cracking. With a lack of industry experience, UHPC specialists face additional challenges in spreading hands-on practice to concrete industry professionals so that the latter can be well versed in applying this sophisticated concrete technology. For these reasons, a comprehensive literature study on recent development trends of UHPC should be conducted to determine its current status and prospects. This article scientifically reviews the current status, carbon capturing capabilities, sustainability aspects, challenges and limitations, and potential applications of UHPC. This state-of-the-art review is aimed at helping scientific researchers, designers, and practitioners widen the use of UHPCs in advanced infrastructure applications. This review will help specialists to develop the design guidelines to enable the widespread application of sustainable UHPC. In doing so, design engineers will be provided with an assurance to fully exploit the high strength and other special properties of UHPC and develop models that can efficaciously estimate the ultimate bearing capacity of UHPC sections under various loading conditions.

Physical, mechanical, thermal and sustainable properties of UHPC with converter steel slag aggregates

This paper aims to utilize converter steel slag aggregates (SSA) to develop sustainable ultra-high performance concrete (UHPC) for multifunctional applications. UHPC mixtures with different particle sizes and contents of SSA are developed by applying a modified packing model. The physical, mechanical, thermal and sustainable properties of the designed UHPC have been explored by analysing bulk density, ultrasound pulse velocity (UPV), water-permeable porosity, mechanical strength, spalling and residual strength after elevated temperature, binder efficiency and heavy metal ions leaching. The results show that the optimized particle distribution of converter SSA up to 5.6 mm could be introduced in sustainable UHPC with high 28-days compressive strength up to 177.8 MPa and low binder content as low as 567.2 kg/m3. The designed UHPC mixtures attain bulk density and UPV up to 3070 kg/m3 and 5236 m/s, respectively, which makes them suitable to be utilized as heavy-weight concrete in the protective shield against nuclear radiation. No obvious explosive spalling and relatively high residual strengths reveal the potential application in heat or fire-resistant concrete. The converter steel slag in form of aggregates in UHPC does not cause negative environmental impacts on CO2 emission and heavy metals pollution, considering the relatively high binder efficiency (0.178–0.313 MPa/(kg/m3)) and non-detectable leaching of B, Cr and V.

Study of nonlinear relationships between dosage mixture design and the compressive strength of UHPC

With advances in building materials research, new materials more suitable for specific applications due to their superior durability and mechanical properties are emerging to meet the requirements of infrastructure construction and maintenance. In this sense, ultra-high-performance concrete (UHPC) is considered one of the most promising materials for concrete construction. However, a traditional UHPC mixture contains large amounts of cement, silica fume, superplasticizer, and other expensive and high carbon footprint components. Hence, several researchers have focused on developing alternative UHPC dosages using locally available materials, including several mineral admixtures, to obtain a more affordable and sustainable UHPC. Therefore, deep knowledge about the relationships between the UHPC dosage and its resulting properties could help to improve these developments. However, these relationships are nonlinear and complex. This paper aims to address this gap by using a random forest model trained with a 931 UHPC mixture collection with 17 input variables and a unique response, namely the UHPC compressive strength. After adjusting a regression model, different tools, such as input variable importance analysis and partial dependence plots, were used to assess the nonlinear relationships between the dosage of UHPC and its resulting compressive strength. In most cases, a proper alignment was observed when the findings provided by these analyses were contrasted with the results provided by other researchers. The results indicated that the inputs with the highest significance on UHPC compressive strength are those related to water content, the packing density, and the quartz powder and superplasticizer dosages, followed by the cement content. Furthermore, mineral admixtures with high amorphous SiO2 content, such as RHA and SF, presented a relevant contribution to the compressive strength, while the other admixtures would seem to have a more modest contribution to it. Finally, it is also worth noting that the machine learning model created might help to create novel UHPC dosages by decreasing the duration and expenses of the experimental campaign by permitting the pre-selection of those components with a superior model response.

Development of green and sustainable ultra-high-performance concrete composite reinforced with date palm fibers

In a sustainable approach, it is essential to reduce the volume of agricultural waste materials in order to minimize environmental and health concerns. To pursue this goal, agricultural wastes, mainly date palm fibers (DPFs), was used as a partial replacement of conventional steel fibers to produce ultra-high-performance concrete (UHPC). The UHPC has been used to describe a steel-fibers-reinforced cementitious composite with a very low water-binder ratio. It is one of the most significant breakthroughs in concrete technology in the 20th century due to its outstanding mechanical performance, such as compressive strength over 150 MPa and flexural strength over 30 MPa. The cost of UHPC is known to be significantly higher compared to ordinary reinforced concrete because it requires large quantities of steel fibers. This paper aims to study the feasibility of utilizing DPFs as a partial replacement of steel fibers to produce green, low-cost and sustainable UHPC. The process of extraction and treatment of the DPFs before incorporating it into the mix design was discussed. Several concrete samples were prepared with different weight percentages of DPFs as a partial replacement of steel fibers (from 0% to 25 wt.%). Compression strength, flexural strength, water absorption, and fresh/hardened densities were experimentally investigated. The morphology and the bonding interface between the fibers and cementitious composite were characterized by scanning electron microscopy (SEM). The results reveal that the DPFs has the potential to be utilized to produce UHPC with comparable performance to the traditional UHPC that is normally reinforced with steel fibers.

Influence of recycled aggregates and carbon nanofibres on properties of ultra-high-performance concrete under elevated temperatures

Research interest in producing sustainable ultra high performance concrete (UHPC) has been increasing recently. This paper focuses on the use of recycled coarse aggregate (RCA) as a replacement for 50% of the total natural coarse aggregate (NCA). Two types of replacements were used, namely, carbon nanofiber (CNF) with 0.25%, 0.5%, 0.75%, and 1% by weight of binder and steel fibers (SFs) with 0.5%, 1.0%, 1.5% and 2% of by weight of the binder. In addition to this, hybrid fibers, i.e. a combination of CNF with SFs were also used for few mixes. Twenty-six mixtures were prepared to evaluate the engineering properties of UHPCs containing RCA and NCA with CNF and SFs. The mechanical properties were evaluated through tests of the compressive, split tensile, and flexural strengths and the modulus of elasticity. The mass and compressive strength losses were examined to evaluate the effect of UHPC exposure to elevated temperatures (200 °C, 400 °C, 600 °C, and 800 °C). The incorporation of NCF, SFs, and RCA negatively affected the workability, and the diameter of the slump flow was reduced to 230 mm for RCF0. 25-SF2.0 mixture. The addition of fiber contributed to the improvement of the concrete properties. The compressive strengths were 151.3 and 146.9 MPa for the NF0 and RF0 mixtures, respectively. In fiber addition to UHPC, the best improvement was achieved at 164.9, 158.6, 158.8, 153.5, 167.9 and 180.9 MPa for the NCF0.5, RCF0.5, NSF2.0, RSF2.0, NCF0.25-SF2.0 and RCF0. 25-SF2.0 mixtures.

Workability, Mechanical Properties and Durability of Sustainable Ultra-High Performance Concrete Incorporating Mineral Admixtures

Workability, Mechanical Properties and Durability of Sustainable Ultra-High Performance Concrete Incorporating Mineral Admixtures

Effect of distribution modulus (q) on the properties and microstructure development of a sustainable Ultra-High Performance Concrete (UHPC)

This paper discusses the effect of distribution modulus (q) on the properties and microstructure development of a sustainable Ultra-High Performance Concrete (UHPC) incorporating gold tailings. To be specific, the Modified Andreasen and Andersen (MAA) model is used to design the UHPC matrix, in which a previously seldom focused value --- distribution modulus (q) is carefully investigated here. The deviation between experimental mixtures and different target curves (with different q) are concluded based on Weighted Residual Sum of Squares (WRSS). Then, the fresh and hardened behaviors of the developed UHPCs with different q value are evaluated. The obtained experimental results show that the declination of q can increase the wet packing density of UHPC. Besides, when the distribution modulus (q) is controlled in the range of 0.17–0.19, a sustainable UHPC with advanced properties and microstructure can be produced. For instance, the compressive strength of the optimum UHPC matrix in this study can reach about 136.2 MPa after curing in standard condition for 28 days. This implies that the normally selected distribution modulus (q) value – 0.23 can not always guarantee the maximum packing density and best characteristics for UHPC matrix.

Characterization of sustainable ultra-high performance concrete (UHPC) including expanded perlite

In this study, the performance of ultra-high performance concrete (UHPC) containing expanded perlite powder (or expanded perlite sand) has been investigated comprehensively. The rheological properties, workability, mechanical properties and durability are determined. Results indicate that the replacement of cement by EP powder significantly reduces the viscosity of UHPC, shortens the V-funnel time, and increases the slump flow. Meanwhile, comparable durability and slightly reduced strength can be obtained with up to 60% EP powder addition. The hydration heat, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) results indicated that EP exhibited pozzolanic activity and promoted the early hydration process. Compared with the effect of the addition of EP powder, the replacement of quartz sand by EP aggregate has no distinct effect on the workability, while leads to a relatively larger strength loss . The more obvious mechanical degradation in specimens with 75% and 100% EP sand is due to the fiber settlement. Additionally, the CO2 emission and cement efficiency value have been calculated, where the results confirm that UHPC containing EP powder as cement replacement (or EP sand as quartz sand replacement) is of remarkable potential to be used as a sustainable building material.

Investigation of Alkali-Silica Reactivity in Sustainable Ultrahigh Performance Concrete

Considering its superior engineering properties, ultrahigh performance concrete (UHPC) has emerged as a strong contender to replace normal strength concrete (NSC) in diverse construction applications. While the mechanical properties of UHPC have been thoroughly explored, there is still dearth of studies that quantify the durability of UHPC, especially for sustainable mixtures made with local materials. Therefore, this research aims at investigating the alkali-silica reactivity (ASR) potential in sustainable UHPC in comparison with that of NSC. Sustainable UHPC mixtures were prepared using waste untreated coal ash (CA), raw slag (RS), and locally produced steel fibers. UHPC and benchmark NSC specimens were cast for assessing the compressive strength, flexural strength, and ASR expansion. Specimens were exposed to two curing regimes: accelerated ASR conditions (as per ASTM C1260) and normal water curing. UHPC specimens incorporating RS achieved higher compressive and flexural strengths in comparison with that of identical UHPC specimens made with CA. ASR expansion of control NSC specimens exceeded the ASTM C1260 limits (>0.20% at 28 days). Conversely, experimental results demonstrate that UHPC specimens incurred much less ASR expansion, well below the ASTM C1260 limits. Moreover, UHPC specimens incorporating steel fibers exhibited lower expansion compared to that of companion UHPC specimens without fibers. It was also observed that the mechanical properties of NSC specimens suffered more drastic degradation under accelerated ASR exposure compared to UHPC specimens. Interestingly, UHPC specimens exposed to accelerated ASR conditions attained higher mechanical properties compared to that of reference identical specimens cured in normal water. Therefore, it can be concluded that ASR exposure had insignificant effect on sustainable UHPC incorporating CA and RS, especially for specimens incorporating fibers. Results indicate that UHPC is a robust competitor to NSC for the construction of mega-scale projects where exposure to ASR conducive conditions prevails.

Experimental Characterization of Prefabricated Bridge Deck Panels Prepared with Prestressed and Sustainable Ultra-High Performance Concrete

Enhanced quality and reduced on-site construction time are the basic features of prefabricated bridge elements and systems. Prefabricated lightweight bridge decks have already started finding their place in accelerated bridge construction (ABC). Therefore, the development of deck panels using high strength and high performance concrete has become an active area of research. Further optimization in such deck systems is possible using prestressing or replacement of raw materials with sustainable and recyclable materials. This research involves experimental evaluation of six full-depth precast prestressed high strength fiber-reinforced concrete (HSFRC) and six partial-depth sustainable ultra-high performance concrete (sUHPC) composite bridge deck panels. The composite panels comprise UHPC prepared with ground granulated blast furnace slag (GGBS) with the replacement of 30% cement content overlaid by recycled aggregate concrete made with replacement of 30% of coarse aggregates with recycled aggregates. The experimental variables for six HSFRC panels were depth, level of prestressing, and shear reinforcement. The six sUHPC panels were prepared with different shear and flexural reinforcements and sUHPC-normal/recycled aggregate concrete interface. Experimental results exhibit the promise of both systems to serve as an alternative to conventional bridge deck systems.

Marine clay in ultra-high performance concrete for filler substitution

This study demonstrated the utilization of marine clay as a substitute to quartz filler in ultra-high performance concrete (UHPC). The clay used in the study, obtained as a waste from excavation works in Singapore, was a low-grade kaolinite clay with 29% kaolinite content. It was dried, ground, and calcined at 700 °C to activate the aluminates through de-hydroxylation. Studies were conducted wherein the calcined marine clay was used to replace quartz powder by 30%, 50%, 70% and 100% by weight (wt.) and investigated for compressive strength, hydration kinetics, phase composition and portlandite consumption. Comparable strength as that of the reference mix was achieved at 30% quartz filler substitution, while higher level of substitutions led to decrease in strength. The results from iso-thermal calorimetry indicate strong nucleation effect due to clay showing substantial acceleration in hydration peaks. The long-term effect on hydration degree was comparable for all mixes as determined from bound water calculated using thermo-gravimetric analysis (TGA). In fact, higher level of substitution affected the amount of portlandite consumption. Overall, this study shows waste marine clay as a viable alternative to costly and carcinogenic quartz powder and hence, provide a new approach for sustainable UHPC.

Optimization and characterization of high-volume limestone powder in sustainable ultra-high performance concrete

This paper aims to optimize high-volume limestone powder in sustainable ultra-high performance concrete (UHPC), and characterize its roles on plasticization effect, hydration kinetics, microstructure and hardened properties. The spread flow, hydration products, compressive strength, porosity and pore structure, shrinkage, embedded CO2 emission and unit cost are investigated with different substitution levels of binders by limestone powder, varying from 0 to 80 vol%. Results show that replacing high volume of binders by limestone powder is an efficient way to develop eco-friendly and low-cost UHPC. Limestone powder shows a positive mineral plasticization effect that should be considered in designing UHPC. The degree of secondary pozzolanic hydration is more intensive than C3S/C2S hydration, which can enhance the later-age strength development potential. An appropriate content of limestone powder can contribute to a higher strength, denser pore structure, diminished total free shrinkage and higher sustainability efficiency. The optimum content of limestone powder appears to be 50 vol% of the total powder content in UHPC.

Optimized design of ultra-high performance concrete (UHPC) with a high wet packing density

This study presents an optimized design method in developing ultra-high performance concrete (UHPC) with high wet packing density, in which the multiply effects of solid and liquid phases on UHPC packing mode are considered. Specifically, a model based on D-optimal method is firstly established to assess the influence of solid granular particles and superplasticizer (SP) on the UHPC packing density. Based on the theoretical analysis, the mixture proportions can be optimized, and UHPC with high wet packing density could be produced. Then, to evaluate the reliability of the math-physical method in developing UHPC, its compressive strength and pore structure are tested. The obtained experimental results show that the designed UHPC contributes high packing density, leading to optimized pore structure and extraordinary compressive strength. The experimental verification further highlights that D-optimal method is a promising and effective approach to design UHPC, and eventually for the development of sustainable UHPC.

Development and properties evaluation of sustainable ultra-high performance pastes with quaternary blends

This study aims to investigate the synergistic effect of quaternary blends applying supplementary cementitious materials on sustainable Ultra-high Performance Concrete (UHPC) pastes. The hydration kinetics, pore structures, fresh behaviour, strength, fibre-to-matrix bond, shrinkage and environmental sustainability of 14 UHPC pastes are determined and analysed. The results show that limestone powder contributes to better environmental sustainability and fresh behaviour, but enlarged shrinkage and diminished strength, and application of silica powder is an effective measure to overcome those disadvantages. Slag cement possessing a relatively lower Ca/Si ratio (2.45) is preferred to a lower amount but finer silica (3% nano silica) in the presence of limestone powder, compared to the Portland cement with a higher Ca/Si (3.22) that needs more silica even with coarser particle size (5% micro silica). Quaternary blends with cement-slag-limestone-silica in UHPC pastes have considerable advantage of reducing embedded CO2 emission and and improving sustainability efficiency. Furthermore, positive synergies in term of strength, fibre-to-matrix bond and total free shrinkage are observed in UHPC pastes with quaternary binders compared to binary and ternary ones.

Optimized treatment of recycled construction and demolition waste in developing sustainable ultra-high performance concrete

This paper addresses an effective way to apply recycled construction and demolition waste (C&D waste) in developing ultra-high performance concrete (UHPC). To be specific, the modified Andreasen & Andersen (A&A) particle packing model is employed firstly to achieve a dense packed structure of UHPC. Secondly, C&D waste is used to replace cement and aggregate synchronously in order to minimize negative effect on the dense packing structure aforementioned. After that, the impact of replacing cement and aggregate by C&D waste on the properties of UHPC is assessed. Experimental results reveal that benefits including reduction of early heat accumulation and auto-shrinkage, low energy consumption are generated when replacing up to 50% of cement and 19% of fine aggregate by C&D waste. In this case, a comparable compressive strength can be obtained. Additionally, the scanning electron microscope (SEM) analysis results also highlight improved microstructure owing to the addition of this solid waste. Conclusively, recycling of C&D waste as filling material in developing UHPC provides a promising view to develop a sustainable cement based material with advanced properties.

The Influence of Granite Cutting Waste on The Properties of Ultra-High Performance Concrete

This study analyzes the effect of using waste by-products generated in the process of granite cutting as part of the granular structure of Ultra High Performance Concrete (UHPC). The manufactured concrete has a compressive strength greater than 115 MPa. This study substitutes 35%, 70% and 100% of the volume of micronized quartz powder (<40 μm) with granite cutting waste. This is an innovative study where the feasibility of using waste from granite quarries as a replacement for micronized quartz in UHPC has been analyzed. The results show an improvement in the workability and compressive strength of UHPC, for all substitution ratios. The flexural strength and tensile strength increase when the substitution ratio is 35%, and even the values obtained for 100% substitution are acceptable. In view of the results obtained in this study, granite cutting waste, instead of the micronized quartz powder usually used, is a viable alternative for the manufacture of expectedly more sustainable UHPC.

Development of a novel cleaner construction product: Ultra-high performance concrete incorporating lead-zinc tailings

This paper addresses a development for a novel sustainable Ultra-High Performance Concrete (UHPC) incorporating lead-zinc tailings. The modified Andreasen & Andersen particle packing model is utilized to achieve a densely compacted cementitious matrix and the lead-zinc tailings are utilized to replace cement by 10%, 20%, 30% and 40% (wt.), while the packing densities of all the designed UHPC mixtures are almost keep the same. Then, the impact of added lead-zinc tailings on the fresh and hardened behaviors of the developed UHPC is investigated. The obtained experimental results reveal that the workability, compressive strength and chlorine anion penetration resistance of the UHPC decrease with the addition of lead-zinc tailings. However, it is possible to develop self-compacting UHPC with up to 30% replacement of cement by lead-zinc. Moreover, it is noteworthy that the addition of lead-zinc tailings could significantly decrease the early autogenous shrinkage of UHPC, which is beneficial for its microstructure development and application. Additionally, the leaching toxicity of heavy metals for this developed sustainable UHPC is far lower than that of the National Standard of China. The ecological evaluation demonstrates that replacing cement by lead-zinc tailings in the production of UHPC can significantly reduce its environmental impact, which provides a promising view for developing and applying a novel cleaner construction product with advanced properties.

Effect of chemical and thermal activation on the microstructural and mechanical properties of more sustainable UHPC

This paper investigates the influence of the content of blast furnace slag (BFS) on the microstructural and mechanical properties of non-activated and activated ultra-high performance concrete (UHPC). Three volume-substitution rates of cement with BFS were explored (30% for UHPC2, 50% for UHPC3 and 80% for UHPC4) and two activation methods, chemical and thermal, were tested. Results show that with 30% of BFS, heterogeneous nucleation prevailed over dilution, accelerating the hydration reaction of cement and increasing the amount of C-S-H formed. C-S-H decreased the porosity of UHPC2 by 18% and 20% respectively at 3 and 90 days. The compressive strengths of UHPC1 (without BFS) and UHPC2 were very similar. For high BFS contents, the dilution effect prevailed and there was less portlandite, which decreased the amount of hydrated products, particularly at early age. As a result, the porosity of UHPC3 and UHPC4 was more than twofold higher than that of UHPC1.To boost the hydration reaction of blended UHPC with a high BFS content, KOH was added. The use of [KOH]3 significantly increased the amount of hydrated products, reducing the porosity of UHPC4 1.6-fold at 3 days and increasing its compressive strength by 42% at the same age. However, this activation mode was not enough to ensure the required compressive strength of UHPC1. Thermal activation at 90 °C for 2 days was therefore tested. Results showed the acceleration of the reaction of solid components, which increased the consumption of portlandite and hence the development of hydrated products. This resulted in improving the packing density of blended UHPC, decreasing its porosity and enhancing its compressive strength. In comparison with reference concrete at 90 days, the compressive strength of UHPC3-T increased by 7% and that of UHPC4 was 12.5% lower.