28d Compressive Strength Research Articles

Research on the preparation and properties of GBFS-based mud solidification materials

Various problems are often encountered during the backfilling process of deep foundation pits. The development of low-cost and efficient solidified materials for the preparation of fluidized solidified soil is currently an ideal solution. This article used industrial solid waste (granulated blast furnace slag, fly ash, carbide slag, etc.) as the main raw material to study the hydration hardening properties of solidified materials and the construction feasibility of fluidized solidified soil prepared from solid waste materials. The results are as follows: Compared with cement-based materials, solid waste-based solidified materials had lower early activity. The cumulative heat release within 72 h was less than 200 J/g. Different solid wastes, such as fly ash and carbide slag, had different effects on the properties of solidified materials. Overall, they had the potential to prepare fluidized solidified soil. The prepared fluidized solidified soil had a fluidity greater than 350 mm, a 28d compressive strength greater than 3 MPa, and exhibited good workability and excellent mechanical properties. Hydration products such as C-S-H and AFt were filled in the soil structure. The 28d compressive strength well above the design requirements of general engineering projects. Meanwhile, the prepared fluidized solidified soil had good adaptability to conventional water reducers (fluidity could be increased by more than 40%) and early strength agents (1d compressive strength could be increased by more than 60%).

Performance evaluation of self-healing recycled concrete using biomineralization modified recycled aggregate as bacterial carrier

The development of bacteria-based self-healing concrete relies on a carrier that is both compatible with the concrete matrix and capable of effectively protecting bacteria. This study utilized biomineralization modified recycled aggregate (RA) as a bacterial carrier to create bacteria-based recycled concrete with a strong self-healing capability. The workability, compressive strength, durability and self-healing performance of concrete were evaluated. The results showed that the quality of RA was significantly improved after biomineralization modification treatment due to the filling of bio-calcium carbonate in surface pores and microcracks, with an increase in apparent density of 1.9%, a decrease in water absorption and crushing index of 13.9% and 15.3%. The modified RA can provide better bacterial protection, thereby enhancing the crack self-healing efficiency of concrete by forming more bio-calcium carbonate healing product. For cracks with a width of about 0.4 mm, after healing of 56 days, the crack width repair ratio of bacteria-based recycled concrete was 94.5%, with an increase by 61.0% compared to that (only 58.7%) of ordinary recycled concrete. X-ray diffraction (XRD) results showed that the bio-calcium carbonate was calcite. The improvement of RA's quality will also benefit the performance enhancement of concrete. Compared to ordinary recycled concrete, the 28d compressive strength of bacteria-based recycled concrete was increased by 16.6%, the capillary water absorption coefficient was decreased by 37.5%, and the workability and resistance to chloride ion penetration was significantly improved.

Reinforcing efficiency of nanomaterials on mechanical and interfacial characteristics of green concrete incorporating fly ash cenosphere

As part of coal-burning ashes, fly ash cenosphere (FAC) has not been extensively used on account of its negative impact on the mechanical performance of concrete. Hence, nanomaterials, i.e., nano-silica (NS) and carbon nanotubes (CTNs), were adopted in this study to enhance the performance of green concrete containing FAC. A chemical etching procedure was presented to arouse the internal curing and pozzolanic activity of FAC and was validated by comparing the physical and chemical properties of raw and treated FAC. The reinforcing efficiency of NS and CNTs on concrete containing raw and treated FAC was evaluated by investigating cement hydration, fresh and mechanical properties, microstructure and interfacial performance. Results showed that nanomaterials had higher enhancing efficiency when they were added to the concrete incorporating treated FAC, as an increase of up to 72.22%, 15.32% and 30.18% in 28-d non-evaporable water, 28-d compressive strength and 28-d split-tensile strength, respectively, was achieved. The internal curing and pozzolanic effects made treated FAC have superior interactions with NS and CNTs, thereby contributing to a denser microstructure and better interfacial performance. With the addition of NS and CNTs, a stiffer ITZ was identified between the treated FAC and mortar given a higher Si/Ca ratio, which alleviated the negative impact of FAC on the mechanical properties of concrete.

Strength development and polymerization reaction mechanism of sulfur-tailings-based geopolymer produced with CaO and Na2SiO3 composite activator

Mining and beneficiation processes are accompanied by the discharge of large quantities of tailings, which occupy large areas of land and cause environmental pollution, which is a significant concern. This study prepared an environmentally friendly geopolymer using sulfur tailings and granulated blast furnace slag (GBFS) and characterized its performance and mechanism analysis. A low-cost and efficient CaO-Na2SiO3 composite activator and comprehensive utilization method for sulfur tailings have been proposed. The experimental results showed that the CaO-Na2SiO3 composite activator can improve the strength of STBG, especially the early strength. The highest 28d compressive strength of STBG can reach 32.2 MPa when the CaO content in the composite activators was 10%. However, when the CaO content in the activators was greater than 10%, the cumulative pore volume and harmful pore volumes of the STBG increased to 0.17 mg/L and 0.07 mg/L respectively, and the compressive strength developed slowly in the later period. In addition, the highest immobilization efficiency of STBG for Cu, Pb, and Mn can reach 99.9%, 93.9%, 91.6% respectively. The STBG can effectively immobilize heavy metals.

Mix ratio optimization and comprehensive performances of novel high-early strength non-shrinkage sleeve grouting material

Considerable infrastructures for urban renewal need fast assembly and daylight open traffic, and it is urgent to develop a novel sleeve grouting material with high-early strength and non-shrinkage (UCGM) for fast connection of assembly structure. Here, sulphoaluminate-Portland cement (S+PC) and high-strength sulphoaluminate clinker and anhydrite (7SA+AH) were used as two binders of UCGMs. The close packing effect of various particle size of dry powders of UCGM was achieved with the closest packing theory. Then, the preliminary mix ratio optimization of UCGM was carried out according to the initial flowability (S0) and 12 h compressive strength (fc12 h) of UCGM. Finally, the mix ratio of UCGM was optimized by further introducing additives and fibers, and the rheological property, mechanical property, expansion rate, durability, and microstructure of UCGMs were comprehensively studied. Results show that, the S0, flowability retention after 30 min (S30 m), fc12 h, 28d compressive strength (fc28d), 3 h expansion rate (P3 h), and the gap between 3 h/24 h expansion rate (GP3–24 h) of UCGM with S+PC and 7SA+AH system are 300 mm, 270 mm, 62 MPa, 128.4 MPa, 0.06%, 0.095%; 300 mm, 280 mm, 82.5 MPa, 106 MPa, 0.025%, 0.11%, respectively. Obviously, the UCGM with S+PC system has superior flowability, faster and longer lasting growth in strength, higher durability, and better in-packing effect for sleeve structure, which is more suitable for fast assembly of urban facilities.

Improvement of shrinkage resistance and mechanical property of cement-fly ash-slag ternary blends by shrinkage-reducing polycarboxylate superplasticizer

Fly ash and slag are two commonly used supplementary cementitious materials (SCMs) in modern concrete, which can significantly enhance the long-term durability of concrete. However, their application is somewhat limited due to the negative impact on early strength development and shrinkage cracking. This study proposed using a recently developed shrinkage-reducing polycarboxylate admixture (SR-PCA) to alleviate the above problems. The effect of SR-PCA on compressive strength, drying shrinkage, autogenous shrinkage, mass loss, pore structure and hydration process were also investigated. The results showed that SR-PCA enhanced the 28d compressive strength due to the refinement of pore structure and improved hydration degree. With the addition of SR-PCA, the drying shrinkage and autogenous shrinkage were significantly reduced, particularly in the mixture blended with 50% fly ash, while showing a slight impact in the sample with 50% slag. SR-PCA decreased the drying shrinkage by lowering the hydrous compressibility factor (CF) value and mesopore volumetric percentage. The incorporation of SR-PCA retarded cement hydration at an early age, thereby reducing the early-age autogenous shrinkage, while the long-term autogenous shrinkage was mitigated due to the enhancement effect on the hydration degree at 28 days. Therefore, SR-PCA is a practical approach for enhancing shrinkage resistance and compressive strength in cement-fly ash-slag blends, thereby contributing to the broader application of these industrial by-products.

Experimental study on the basic properties of new biomass bamboo aggregate concrete

Gravel aggregate is an important part of concrete, but the resources of natural aggregate, such as gravel, are increasingly scarce and may have adverse effects on the environment. Therefore, a new biomass bamboo aggregate concrete was proposed in this study, which bamboo aggregate was used to replace gravel aggregate to alleviate the shortage of gravel resources. To study the basic properties of bamboo aggregate concrete and explore its feasibility, tests for compressive strength, splitting tensile strength, flexural strength, and uniaxial compressive stress-strain curve were conducted. The microstructure was also observed. The research parameters included the concrete curing age and different bamboo aggregate volume replacement ratios. The results presented that the mechanical properties of bamboo aggregate concrete were enhanced with increasing age. Compared with the normal concrete, the mechanical properties of bamboo aggregate concrete decreased as the replacement ratio of modified bamboo aggregate increased, but the 28-d compressive strength of modified bamboo aggregate concrete could still reach 74% of that of normal concrete. The mechanical performance of bamboo aggregate concrete was significantly influenced by whether bamboo aggregates were modified. The uniaxial compressive stress-strain model proposed by GB50010-2010 was suitable for bamboo aggregate concrete. The interfacial bonding effect between modified bamboo aggregate and cement matrix was improved.

Improvement on durability of concrete by early age continuous loading treatment

This study investigated the effect of different pressure levels of continuous loading (2.5 MPa, 5.0 MPa, 7.5 MPa, and 10.0 MPa) on the enhancement of concrete durability and proposed the underlying mechanisms behind. To evaluate the efficiency of continuous loading, in addition to compressive strength, the durability, including chloride ion permeability, freeze-thaw resistance and carbonation resistance of the concree were determined, and the micro-scale investigation, including pore structure, microhardness, hydration product and microstructures were conducted. The results showed that, compared to reference (non-pressurized sample), the continuous loading process increased the 28d compressive strength of concrete by 10.3% to 27.4%, decreased chloride ion migration coefficient by 34% to 48.9%, increased freeze-thaw cycles by 20%, and reduced the carbonation depth by 12.3% to 36.2%. The improved performance was attributed to the enhancement of pore structure and reduction of ITZ width, which was a result of multiple factors such as increased compaction and improved movement of free water.

Effects of alkali activator on the chloride-ion permeability of one-part alkali-activated nickel slag concrete

Herein, the effects of the ionic types and content of alkali activator on the chloride-ion permeability of one-part alkali-activated nickel slag concrete were examined. The NT Build 492 method was adopted to measure the Cl− transport performance. In general, the total Cl− concentration in concrete decreases with the increase of penetration depth; however, the enrichment of Cl− concentration in the sample is not obvious. Anions have more effect on 28-d compressive strength, while cations have more effect on chlorine-ion permeability. For the same Na2O content, SiO32−-activator and Na+-activator perform better than other anions and cations, while OH– and K+ perform worse than other ions. The chloride-ion permeability coefficient (DRCM) of concrete with Na2SiO3 is the lowest and that with KOH is the highest. The DRCM of concrete prepared with KOH is 1.93 times higher than that of concrete prepared with Na2SiO3. When the activator is Na2SiO3, the DRCM of concrete decreases with the increase in Na2O content when the Na2O content is less than 7%. However, when the Na2O content exceeds 7%, the DRCM of concrete increases with the increase in Na2O content.

Thermal activation and mechanical properties of high alumina coal gangue as auxiliary cementitious admixture

In order to use high alumina coal gangue as auxiliary cementitious admixture via a simple and convenient thermal activation technique, the thermal transformation, mineral phase transformation and structure changes of coal gangue at calcining temperatures of 500–1000 °C were analyzed using x-ray diffraction (XRD), differential thermal Analysis (DTA), thermogravimetry (TG), infrared analysis (IR) and scanning electron microscope (SEM). The mechanical properties of cement mortar with 30% coal gangue auxiliary cementitious admixture were also measured to determine the optimal calcining temperature. As calcining temperature was increased, the coal gangue experienced the following transformations: carbon combustion, dehydroxylation, metakaolin transformation and mullite transformation. The cement mortar with coal gangue auxiliary cementitious admixture calcined at 700 °C presented the highest 28-d flexural and compressive strength, increasing by 8.27% and 11.85% respectively as compared with the benchmark cement mortar. The maximum dosage of coal gangue auxiliary cementitious admixture in cement mortar was further identified to be less than 30% by mechanical properties testing. The activity of high alumina coal gangues at different calcining temperatures was explained from the view points of hydration degree and products. The present investigation can provide a useful reference to utilize high alumina coal gangue as auxiliary cementitious admixture by means of a simple thermal activation at 700 °C.

Preparation of Cementitious Materials from Mechanochemically Modified Copper Smelting Slag Compounded with High-Aluminum Fly Ash.

Copper smelting slag discharged from mining and high-aluminum fly ash generated during the combustion of coal for energy production are two typical bulk solid wastes, which are necessary to carry out harmless and resourceful treatment. This research proposed an eco-friendly and economical method for the co-consumption of copper smelting slag and high-aluminum fly ash. Cementitious materials were compounded with copper smelting slag and high-aluminum fly ash as the main materials were successfully prepared, with a 28-d compressive strength up to 31.22 MPa, and the heavy metal leaching toxicity was below the limits of the relevant standards. The optimum mechanical properties of the cementitious materials were obtained by altering the material proportion, ball mill rotation speed, and CaO dosage. Under the combined effect of mechanical ball milling at a suitable speed and chemical activation with a certain alkali concentration, the prepared cementitious materials had an initial activation. The pastes of the cementitious materials generated a gel system during the subsequent hydration process. The two steps together improved the mechanical strength of the cured products. The preparation was simple to operate and offered a high stability of heavy metals. The heavy metal contaminants were kept at a low content throughout the process from raw materials to the prepared cured specimens, which was suitable for application in practical environmental remediation projects and could provide effective solutions for ecological environment construction.

Application of sulfate ion fixation in internal sulfate attack: The gel containing barium salt

Sulfate attack is one of the most important factors affecting the durability of concrete, and the corrosion sources of internal sulfate attack (ISA) mostly come from the raw materials of concrete. Adding corrosion resistance admixtures to concrete is one of the most effective ways to prevent internal sulfate attack. By wrapping barium salt with SA gel, the modified barium chloride admixture (MB) is obtained which can exist stably in concrete and release barium ions to form barium sulfate in a sulfate environment. The modified barium salt has little effect on the cement workability and hydration process and even can improve the mechanical properties slightly. When the MB content reaches 6% (MB-6), the strength improvement effect is most obvious. Compared with the P-0, the 7d compressive strength of MB-6 is increased by 9.14%, and the 28d compressive strength is increased by 5.77%. It can be seen by SEM that the amount and crystal size of ettringite in the cement mixed with admixtures are reduced. The corrosion resistance of the matrix can be further improved by using a modified barium chloride-silica fume composite admixture (MB-F). After 90 days of internal sulfate attack, the strength of the MB-F even improves slightly. When the modified barium chloride to silica fume ratio is 4:6, the cement-based material achieved the best resistance to internal sulfate attack. In addition to MB, which can make sulfate ions fixation and inhibit the formation of ettringite, silica fume can also consume calcium hydroxide and generate more C-S-H gel, which compacts the weak part of the matrix and greatly improves the resistance to internal sulfate attack of cement-based materials. It provides the possibility for the application of modified barium salt in external sulfate attack.

Thermal Activation of High-Alumina Coal Gangue Auxiliary Cementitious Admixture: Thermal Transformation, Calcining Product Formation and Mechanical Properties.

In this paper, a new preparation technology is developed to make high-alumina coal gangue (HACG) auxiliary cementitious admixture by calcining HACG-Ca(OH)2 (CH) mixture. HACG powders mixed with 20 wt.% CH were calcined within a temperature range of 600-900 °C, and the thermal transformation and mineral phase formation were analyzed. The hydration reaction between activated HACG-CH mixture and cement was also investigated. The results showed that HACG experienced a conventional transformation from kaolinite to metakaolin at 600 °C and finally to mullite at 900 °C, whereas CH underwent an unexpected transformation process from CH to CaO, then to CaCO3, and finally to CaO again. These substances' states were associated with the dehydroxylation of CH, the chemical reaction between CaO and CO2 generating from the combustion of carbon in HACG, and the decomposition of CaCO3, respectively. It is the formation of a large amount of CaO above 800 °C that favors the formation of hydratable products containing Al2O3 in the calcining process and C-A-H gel in the hydration process. The mechanical properties of HACG-cement mortar specimens were measured, from which the optimal calcination temperature of 850 °C was determined. As compared with pure cement mortar specimens, the maximum 28-d flexural and compressive strengths of HACG-cement mortar specimens increased by 5.4% and 38.2%, respectively.

Enhanced thermo-mechanical properties of cementitious composites via red mud-based microencapsulated phase change material: Towards energy conservation in building

Integrating microencapsulated phase change materials (PCMs) into cement-based materials can endow building with huge heat storage capacity. Nevertheless, cement-based materials containing microencapsulated PCMs universally behave deteriorated mechanical and heat transfer properties. In this study, a capric acid and paraffin eutectic PCM (CA-PA) was prepared, and it had a large latent heat (143.4 J/g) with the suitable melting point (27.1 °C) used for building applications. Then, a novel microencapsulated PCM was proposed by the three-step method including the construction of red mud-based geopolymer hollow microsphere (RMHM), the impregnation of CA-PA and the surface grafting of nano-SiO2. A comparative study was performed to unveil the influence mechanism of different surface properties of the synthetic red mud-based microencapsulated PCMs (namely CA-PA/RMHM and CA-PA/RMHM@SiO2) on the microstructure, mechanical and thermal properties of cement mortar. It turned out that the 28d compressive strength and thermal conductivity of the cement mortar with replacing 20 % sand by CA-PA/RMHM were 26.7 MPa and 0.7165 W/m·K, which were increased by 41.6 % and 14.7 % due to introducing nano-SiO2 coating. Besides, energy and environmental assessment indicated that using mortar with CA-PA/RMHM@SiO2 in building had good energy saving performance and great potentials for emission reduction.

Effects of CO2-absorbed triethanolamine solutions on strength development of cement mortars and the mechanism: Synergism of cement hydration and carbonation

In this study, the impacts of CO2-absorbed triethanolamine solutions (TEA-CO2) on the mechanical property, phase composition and micro-structure of cement mortars were investigated. The results showed that TEA-CO2 addition increased the 1d, 3d, and 28d compressive strength by 47%, 19%, and 4%, respectively, which suggests a synergistic effect of triethanolamine and absorbed CO2 on strength development of cement mortars. The enhancement is due to TEA-CO2 accelerates hydration of aluminate and silicate phases in early age. TEA-CO2 facilitated CaCO3 formation to increase cement hydration degree and modify the pore structures. However, the hydration of silicate phases was delayed slightly by TEA-CO2 at 28d. The above results provide theoretical support for further utilization of CO2 in cementitious materials.

Propriedades no estado fresco e endurecido de compósitos cimentícios com a adição de celulose nanofibrilada

Abstract Evaluating the effects of nanomaterials in cementitious systems is paramount to projecting high-performance construction materials. However, the synthesis of some nanomaterials on a large scale and their toxicity may limit their application. In this context, nanofibrillated cellulose (NFC), a biodegradable and natural material stand out. Thus, this paper aims to study the influence of NFC on the fresh, hardened properties (compressive and flexural strengths) and mineralogy of cementitious systems. The results indicated that incorporating up 0.075 wt.% to CNF reduced the spread of cement pastes by up to 14.0%. A CNF content of 0.025 wt.% increased the 28-d compressive and flexural strengths by 22.0% and 25.0%, respectively, compared to the control sample. The X-ray diffraction (XRD) results indicate that higher NFC contents (>0.025 wt.%) resulted in lower intensity portlandite peaks after 7 days, which may show a lower hydration degree, especially concerning the plain cement paste. These results suggest that the NFC can affect the hydration of cementitious matrices at early ages; however, it did not significantly affect the hydration degree after 28 days of hydration.

A Study on Chloride Corrosion Resistance of Reactive Powder Concrete (RPC) with Copper Slag Replacing Quartz Sand under Freeze-Thaw Conditions.

In order to study the influence of freeze-thaw cycles on chloride ion corrosion resistance of RPC with copper slag (CS) instead of quartz sand (QS), the 28d uniaxial compressive strength (UCS) of CSRPC with a different CS substitution rate was investigated by unconfined compression tests. The electric flux test method was used to study the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles, and the pore size distribution was obtained through the nuclear magnetic resonance (NMR) method. Then, a mathematical relationship between the chloride ion diffusion coefficient and the pore fractal characteristic parameter T was established to study the effect of freeze-thaw cycles on chloride ion diffusion. Finally, SEM/EDS, XRD, and DTG methods were combined to study the influence of the distribution of Friedel's salts generated after freeze-thaw cycles on chloride ion diffusion in CSRPC. The results indicate that CS has a micro aggregate effect and pozzolanic activity, which can effectively improve the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles. In addition, the electric flux of CSRPC decreases with the increase in freeze-thaw cycles, and the chloride diffusion coefficient is closely related to the pore fractal dimension.

Limestone calcined clay cement (LC3): A sustainable solution for mitigating environmental impact in the construction sector

The impact of global warming on the construction sector is a serious issue in today's world; this might be attributed to the emission of greenhouse gas (GHG) during the production process of Portland cement. Due to its advantages, cement plays a major role in the construction of civil infrastructures. Cement production is not only responsible for global warming and also creates a risk of raw material deficiency. To reduce the over exploitation of virgin materials, Limestone Calcined Clay Cement (LC3), with a proportion of Clinker 50 %, Limestone 30 %, Calcined Clay 15 % and gypsum 5 %, is found to be a suitable and sustainable alternative to preserve the ecosystem. As a result, attempts were undertaken in this work to create a mixture design approach for LC3 with the primary objective of developing higher compressive strength (CS) in a cost-effective manner. The relationship between the water to binder ratios and 28-d CS has been examined to suggest a conceptual mixture design strategy for LC3 rationally. The 28-day CS of 46.2 MPa has been observed. The suggested design technique has been presented step by step and validated using an example based on the guidelines illustrated by IS 10,262. The design technique aims to produce a concrete mix that meets specific strength, workability, and durability requirements while considering the environmental conditions and properties of materials available. The study emphasizes a systematic approach to concrete mix design, considering various factors like water-cement ratio, aggregate proportions, and workability requirements to ensure the resulting concrete meets the desired performance standards. Compliance with IS 10,262:2019 ensures that concrete used in construction is designed systematically and according to established guidelines, leading to higher quality and more predictable performance in structural applications. Further, to access the sustainability of the developed LC3 mix Life-Cycle Assessment (LCA) of LC3 was reported starting from raw material procurement to the production of concrete as the final product. In this LCA analysis, the monetary cost involved in the production of concrete, energy demand and GHG emission of the LC3 was compared with the conventional concrete. The result from the analysis revealed that LC3 possess superior performance in terms of energy requirement and GHG emission than the OPC concrete.

Development of high-strength lightweight concrete by utilizing food waste digestate based biochar aggregate

The application of carbon-negative biochar in cement composites can effectively reduce carbon emissions of construction materials. In this study, low-carbon composites were tailored with high volume of food waste digestate (FWD) biochar aggregate. The biochar was customized at different temperatures with the goal of enhancing the properties of cement-based composites. Backscattered electron microscopy (BSEM) images show that FWD biochar with a grey circle shape exhibited strong bonding with the cement matrix. Nano-indentation results indicate that the two statuses of FWD biochar showed visco-elastic and elastic-plastic modes of deformation, respectively. The FWD biochar aggregate prepared at higher pyrolysis temperatures (i.e., 650 °C and 750 °C) has higher elastic modulus (up to 11.4 GPa), which can be applied to make biochar blocks with higher strength and lower density compared to the biochar pyrolyzed at 550 °C. As a result, FWD 750BC blocks could reach 28-d compressive strength of 57.8 MPa and density of 1.77 g cm−3, which fulfilled the requirements of high-strength lightweight aggregate concrete. Hence, this study established a foundation to utilize FWD biochar as an aggregate in high-strength biochar construction materials.

Physical, mechanical and microstructural properties of one-part semi-lightweight geopolymers based on metakaolin modified with gypsum and lime

The elemental composition of precursors is crucial for the performance development of geopolymers. Metakaolin (MK) was used to produce one-part geopolymers (OPG), and the influence of calcium-based components (lime and gypsum) on their properties was investigated. The experimental results show that the use of lime instead of MK increases the fluidity of the mixture, while the addition of gypsum decreases the fluidity. Meanhwlie, the use of lime to replace a small amount of MK increases the concentration of activator by consuming water and the dissolution of calcium ions also participates in the geopolymerization reaction, which enhances the mechanical properties and durability of OPG. When 10 % lime is applied, the 7-d and 28-d compressive strengths of OPG are increased by 210 % and 157.14 % compared with the plain sample, respectively. The addition of gypsum generates AFt in OPG, which reduces the compactness of the microstructure, which is not conducive to the development of the strength and durability of OPG. When 10 % gypsum is applied, the 28-d compressive and flexural strengths of OPG are decreased by 32.14 % and 26.67 % compared with plain samples, respectively. As the lime content increases, further addition of gypsum to OPG has a more negative effect on OPG due to the plundering of calcium ions in the lime. The 28-d dry density of OPG is between 1585 and 1729 kg/m3, which makes it have a lower thermal conductivity (0.87–0.94 W/m·K).