https://doi.org/10.11112/jksmi.2024.28.6.1

이용준(Yong-Jun Lee) ; 선종완(Jong-Wan Sun) ; 임종권(Jong-Kwon Lim) ; 박경훈(Kyung-Hoon Park)

An Internet of Things (IoT)-based monitoring system is being constructed with the objective of facilitating rational maintenance decisions and ensuring the safety of domestic bridges that are experiencing continuous aging. In the context of a large number of total managed bridges, it is essential to undertake a rational evaluation of those that require a high level of management in order to select appropriate measurement targets. In order to achieve this objective, a methodology was devised to assess the risk level of the all bridges, taking into account a range of influencing factors, then employed to determine the relative priority of bridges requiring measurement. A total of more than 8,000 bridges were evaluated in comprehensive management levels (CML) 1 to 5 based on risk and criticality, and 1,933 bridges were selected as CML 4 and 5 bridges requiring higher management levels. A statistical analysis of actual bridge deterioration, damage, and damage cases, as well as CML, revealed that the selected bridges were older, more heavily trafficked, and had lower safety ratings on average than other bridges. It is believed that the relative risk and criticality of all bridges were appropriately considered and selected, and that the proposed bridge risk assessment method will prove useful for various maintenance decision-making problems of facilities in the future.

https://doi.org/10.11112/jksmi.2024.28.6.12

김경현(Kyung-Hyun Kim) ; 김기현(Ki-Hyun Kim) ; 백인열(In-Yeol Paik)

As part of a study to analyze the excessive camber occurring in prestressed concrete railway bridges, this paper develops a time-dependent camber analysis program for concrete structures and analyzes the change in camber according to the variation of applying time and duration of prestressing force and self-weight as well as the change in live load. The incremental time-step analysis method is applied in order to consider time-related variables such as the strength of concrete in early stage, the applying time and duration of the prestressing force and loads, and the decrease in prestressing force over time. The equations for calculating the creep coefficient and loss of prestressing force are applied according to the domestic bridge design codes. By applying the developed method to an example PSC composite beam for railway bridge, the instantaneous deflection at various loading points and the long term creep deflection for the loading period are obtained. Also the effect of reducing the camber is examined when the prestressing force is reduced considering the degree of allowance of the railway live load. Through numerical examples, it can be shown that the camber increases if the initial prestressing force is introduced early or the period to the slab placement is long or a combination of the two. When the live load is reduced by taking into account the actual train weight, the camber is reduced.

https://doi.org/10.11112/jksmi.2024.28.6.23

이빛나(Binna) ; 이종석(Lee)

This study measured the compressive strength and ultrasonic pulse velocity of various concretes exposed to the domestic environments for approximately 15 years, and investigated the relationship between the compressive strength and ultrasonic velocity. The test specimens were divided into three types (w/c 40%, 50%, and 60%) according to the water/cement ratio using ordinary portland cement and three types (blast furnace slag, fly ash, and silica fume) according to the type of admixture. The analysis of the compressive strength showed that, regardless of the specimen type, the compressive strength increased with age. As a result of analyzing the ultrasonic velocity according to the type of water/cement ratio, the ultrasonic velocity showed a tendency to increase as the water/cement ratio decreased and as age increased, and the ultrasonic velocity at 15 years of age increased by about 0.11 to 0.20 km/s compared to the ultrasonic velocity at 28 days of age. The results of ultrasonic velocity according to the type of admixture also showed that the ultrasonic velocity tended to increase as the age increased, and the velocity increased by about 0.08 to 0.38 km/s compared to the ultrasonic velocity at 28 days. As a result of the correlation between compressive strength and ultrasonic velocity according to the type of water/cement ratio, a linear relationship was shown in which ultrasonic velocity increased as the water/cement ratio decreased. Meanwhile, the results of analyzing the correlation between the compressive strength and ultrasonic velocity according to the type of admixture showed a lower correlation between compressive strength and ultrasonic pulse velocity.

https://doi.org/10.11112/jksmi.2024.28.6.31

허인욱(In-Wook Heo) ; 이규빈(Kyu-Bin Lee) ; 이상기(Sang-Ki Lee) ; 함승희(Sunnie Haam) ; 최승호(Seung-Ho Choi)

In this study, an analytical evaluation of the structural safety of mechanical parking systems under fire conditions was conducted. Fire Dynamics Simulator (FDS) was employed to perform fire simulations with variables such as the presence or absence of sprinkler operation, the number and location of sprinklers, and the application of fire shutters and fire-resistant boards, to determine the heat exposure temperatures of parking pallets. Additionally, a thermo-structural performance analysis of the parking pallets was conducted based on the derived temperatures to assess deformation and stress distribution under fire scenarios. The impact of sprinkler location and operating conditions on the fire resistance performance of parking pallets was evaluated, and optimal sprinkler placement conditions were proposed to minimize fire spread and structural damage.

https://doi.org/10.11112/jksmi.2024.28.6.39

유용래(Yong-Rae Yu) ; 유훈(Hoon Yu) ; 안호준(Ho-June Ann) ; 이종재(Jong-Jae Lee)

During the industrialisation of the 1980s, many bridges were built in Korea and various continuity methods were applied. As time passed, the ageing of these bridges became an issue, making load-carrying capacity evaluations essential. In particular, PSC girder bridges built in the early 1980s have partial continuity, requiring specific modelling and evaluation methods. The model updating method that reflects the actual condition of the bridge can accurately predict and evaluate its behavior, thereby enhancing the reliability of the load-carrying capacity evaluation. The conventional load-carrying capacity evaluation methods have primarily targetting on fully continuous bridges; however, partially continuous bridges exhibit different load transfer characteristics, necessitating a differentiated approach. This study focuses on partial continuity in continuous bridges and suggests a method for load-carrying capacity evaluations, verified through field tests. Unlike previous studies that primarily focused on fully continuous bridges, this study aims to enhance the accuracy and reliability of load-carrying capacity evaluations for partially continuous bridges by proposing modeling and evaluation methods specifically tailored to these structures. Also, this study differentiates itself from previous research by improving the finite element model (FEM) to reflect the characteristics of bridges with only the deck slab made continuous. This improvement was validated using data from load tests conducted on actual bridges, confirming its potential for field application. The finite element model (FEM) was improved to reflect the characteristics of the bridge. Data from Ambient Vibration Tests was used to improve the finite element model, resulting in a close match with the actual behavior of partially continuous bridges and confirming the model's ability to precisely evaluate load distribution and deflection., with errors between the updating FEM and measured deflections ranging from 0.8% to 3.9%, demonstrating its effectiveness.

https://doi.org/10.11112/jksmi.2024.28.6.49

최지완(Ji-Woan Choi) ; 황지원(Ji-Won Hwang) ; 권성준(Seung-Jun Kwon)

The sulfate diffusion coefficient is an important durability design factor for evaluating sulfate-deterioration depth, and it varies with exterior temperature. In this study, the materials used for UAE nuclear power plant were delivered and concrete was prepared with the materials, and the sulfate diffusion coefficient was evaluated. The diffusion coefficients were obtained from 20°C to 50°C with 10°C intervals through natural diffusion test, and the probabilistic information for the diffusivity was derived through average and standard deviation from 3 samples. In addition, the diffusion coefficients were quantified as a function of temperature through nonlinear regression analysis. For the 1-D deteriorated section due to sulfate ingress, compressive strength evaluation technique was proposed with three parameters which can handle the increasing deterioration depth due to raised temperature. The proposed technique effectively showed the increasing diffusivity and the reduced compressive strength with increasing temperature.

https://doi.org/10.11112/jksmi.2024.28.6.56

염우성(Woo-Sung Yum) ; 권도영(Do-Young Kwon) ; 추용식(Yong-Sik Chu)

In this study, various types of silane coupling agents were applied to enhance the bond strength of the glass fiber, which functions as ribs on the surface of carbon fiber reinforced polymer (CFRP) rebars, and the resulting changes in physical properties were investigated. Using glass fiber composites, the optimal composition ratio of silane coupling agents was derived. Subsequently, CFRP rebars with a diameter of 10 mm were fabricated, and tensile strength, elastic modulus, and bond strength with concrete were tested. Initially, based on experimental results regarding the presence or absence of sizing on glass fibers and the type of silane coupling agent, the GS-3TPM sample exhibited the highest improvement rate, making it the optimal composition. The CFRP rebars manufactured with GS-3TPM showed approximately 5% higher tensile strength and elastic modulus compared to conventional CFRP rebars, and the bond strength with concrete improved by about 20%. This study confirmed that the application of silane coupling agents effectively enhances the bond strength between CFRP rebars and concrete.

https://doi.org/10.11112/jksmi.2024.28.6.61

김상우(Sang-Woo Kim) ; 이선호(Sunho Lee) ; 최연제(Yeonje Choi) ; 이정윤(Jung-Yoon Lee)

This paper presents experimental results on the reduction of shear strength in reinforced concrete deep beams subjected to indirect loads from supported beams. The primary experimental variables are the load transfer path and the location of the load-transfer beam. The load transfer path is categorized into direct and indirect loads. The specimens subjected to indirect loads consist of a reinforced concrete deep beam and load-transfer beams that are supported and perpendicular to it. The location of the load-transfer beams is categorized into upper and lower positions of the deep beam. The specimen with load-transfer beams positioned at the bottom was designed to include hanger reinforcement for shear strengthening, aiming to evaluate the effect of the hanger reinforcement. The shear span-to-depth ratio of the supporting beam for all specimens was uniformly 0.7. The experimental results showed that the shear strength of specimens subjected to indirect loads was significantly decreased compared to those subjected to direct loads, with the reduction in shear strength increasing as the position of the load-transfer beam moved lower. Additionally, the position of the load-transfer beams was found to affect the distribution and magnitude of the concrete compression strut as well as the strain in the tension reinforcement.

https://doi.org/10.11112/jksmi.2024.28.6.69

김기현(Gihyeon Kim) ; 김병현(Byunghyun Kim) ; 이사현(Sahyun Lee) ; 조수진(Soojin Cho)

This study proposes a framework for damage detection in structures through vibration responses using semi-supervised learning of an LK-Block Encoder, and validated through experiments with a shear building. The framework utilizes an LK-Encoder, which is composed of four serially connected 1-D CNN-based hidden layer blocks, and applies semi-supervised learning to set a threshold in the feature space for distinguishing between normal and damaged vibration data, thereby enabling damage detection from vibration data. To validate this approach, the study assumed damage scenarios by varying the thickness of shear building columns, and damage detection was conducted using the proposed framework. Results showed an accuracy of 97.03% for large damage condition. When the dataset of the normal condition was increased fourfold, small damage was detected with an accuracy of 99.66%. Additionally, it was confirmed that even when the model was trained with different types of damage from the target detection, increasing the amount of normal data improved damage detection accuracy. These results indicate that the proposed framework effectively detects even minor damage, which is difficult to identify through natural frequency analysis, with high accuracy.

https://doi.org/10.11112/jksmi.2024.28.6.81

송용(Yong Song) ; 이현호(Hyun-Ho Lee) ; 허무원(Moo-Won Hur)

In this study, in order to improve the performance of wall-type apartment RC coupling beams, a steel rod damper was applied to the coupling beams. The test variable was the number of steel rods, and a total of 4 test specimens were made. As a result of the material test of the steel rod, it was evaluated as conforming to KS standards. As a result of the test, it was evaluated that the stress was concentrated in the steel rod and not in the welded area of the steel rod and connection plate. The maximum strength was evaluated to increase linearly, but not proportionally, as the number of steel rod dampers increased.

https://doi.org/10.11112/jksmi.2024.28.6.88

마수빈(Su-Been Ma) ; 이민진(Min-Jin Lee) ; 양다현(Da-Hyeon Yang) ; 정현진(Hyun-Jin Jung) ; 이종한(Jong-Han Lee)

This study introduces a technique for generating parametric BIM models of retaining walls using point cloud data (PCD). Efficient maintenance requires reflecting the current representation of retaining walls, accounting for any discrepancies between the as-built structure and initial drawing. For this, a RANSAC-based algorithm was employed to extract the height and path coordinates from acquired and refined PCD. BIM models were then automatically generated by defining sectional parameters. Applied to a real retaining wall, the algorithm demonstrated a maximum height extraction error of 1.77% and a path coordinate extraction error of 0.88%. This method offers a way to automatically generate BIM models, even when basic data is limited, and there is a the potential to enhance the efficiency of retaining wall maintenance.

https://doi.org/10.11112/jksmi.2024.28.6.95

정현진(Hyun-Jin Jung) ; 김유빈(Yu-bean Kim) ; 박기태(Ki-Tae Park) ; 김재환(Jae-Hwan Kim) ; 이종한(Jong-Han Lee)

As the aging of domestic bridges progresses, concern about safety risks caused by deterioration are growing, which highlights the need for preventive maintenance. The current maintenance system relies largely on reactive measures following inspections, which limits the ability to efficiently monitor damage progression and timing. To address these challenges, this study aims to analyze the correlation between bridge damage scenarios and environmental deterioration factors based on inspection and diagnostic data. Data were classified into four key categories: region, construction year, deicing salt attacks, and freeze-thaw cycles, in order to derive patterns of damage occurrence. This approach enables an analysis of damage scenario trends at the overall component levels and evaluates the impact of single and compound damage scenarios at the component unit level. The study proposes a data-driven preventive maintenance plan that reflects both the structural and environmental characteristics of bridges.The findings are expected to enhance the reliability of bridge maintenance systems and provide foundational data necessary for developing future monitoring and predictive systems, ultimately contributing to the long-term performance and safety of bridges.

https://doi.org/10.11112/jksmi.2024.28.6.104

유용래(Yong-Rae Yu) ; 유훈(Hoon Yu) ; 안호준(Ho-June Ann) ; 이종재(Jong-Jae Lee)

In structural health monitoring, various sensors are used to measure physical quantities and assess the condition of structures. Among these, strain measurement enables both global and local assessment. However, conventional electrical resistance strain gauges perform point measurements, which makes it challenging to evaluate the global condition of a structure. To overcome this limitation, distributed fiber optic sensors have been investigated. However, structural conditions are influenced not only by loads but also by environmental factors such as temperature and humidity. Therefore, to achieve accurate condition assessment, it is necessary to compensate for the effects of temperature. In this study, a method to compensate for temperature effects is proposed using strain data obtained from a BOCDA-based distributed fiber optic sensor. The proposed method is based on the theory that strain caused by temperature and strain caused by load (or damage) are independent. The method eliminates the temperature effect by calculating strain data at a temperature similar to the measured temperature using a basis vector and applying an inner product technique. To validate the proposed method, indoor experiments were conducted using an aluminum specimen and a temperature chamber. The results demonstrated that dynamically updating the compensation values based on the measurement environment allowed for the accurate identification of values and locations similar to the applied load.

https://doi.org/10.11112/jksmi.2024.28.6.116

김민영(Min-Young Kim) ; 박성호(Sung-Ho Park) ; 최경규(Kyoung-Kyu Choi)

This study suggested a method to derive the dynamic characteristics and the stiffness of multi-story frame structures using acceleration data. To achieve this, A Four-frame structure was fabricated, and shaking table tests were conducted. To evaluate the effects of seismic excitations characteristics, two recorded seismic excitations and one artificial seismic excitation with various frequencies were applied. The natural frequencies, damping ratios and mode shapes were derived from acceleration measurements using transfer function. And using these dynamic characteristics, Stiffness was calculated and calibrated. In addition, the derived dynamic characteristics and stiffness were applied to a four-degree-of-freedom (4-DOF) analytical model. An elastic time-history analysis was conducted, and the results were compared with the shaking table test results to validate the reliability of the method.

https://doi.org/10.11112/jksmi.2024.28.6.127

이용준(Yong-Jun Lee) ; 박경훈(Kyung-Hoon Park) ; 선종완(Jong-Wan Sun)

The asset value of social infrastructure must be accurately evaluated, as it is an essential element for rational decision-making processes aimed at efficient asset management. Current domestic accounting guidelines stipulate that the asset value of social infrastructure should be evaluated based on the depreciated replacement cost using the straight-line method. However, while these guidelines state that the remaining service life and useful life should be estimated by a reasonable method, they do not provide specific methods for estimation. In this paper, a performance deterioration model for road tunnels was developed using safety grade information collected through inspections and diagnoses, and formulas for estimating the remaining service life and useful life based on this model were proposed. The Performance and Service Life Based Depreciation (PSLBD) method proposed in this paper is easy to apply as it conforms to the depreciated replacement cost evaluation formula of the existing domestic accounting guidelines. Moreover, since the performance improvements from maintenance actions such as repairs and reinforcements are reflected in the asset value, it is expected that the asset value can be used as a factor in decision-making. Additionally, the proposed valuation method is considered to provide more objective and realistic results compared to existing methods, as it takes into account the performance of tunnels.

https://doi.org/10.11112/jksmi.2024.28.6.135

이선목(Sun-Mok Lee) ; 조성우(Sung-Woo Cho) ; 이병재(Byung-Jae Lee)

In this study, the compressive strength and elastic modulus, adhesion and flexural tensile strength according to the incorporation of redispersible polymer powder into cement-based mortar, which is the most commonly used repair material for concrete section restoration, were examined, and further, the crack resistance and chloride ion penetration resistance were measured to evaluate the volume stability and durability. As a result, the compressive strength and elastic modulus evaluation results showed that the compressive strength and elastic modulus tended to decrease as the amount of VAE polymer added increased. The bond strength and flexural strength showed that tended to increase as the polymer mixing ratio increased. The crack resistance showed that the higher VAE polymer mixing ratio, the more delayed the crack initiation period was. This is believed to be the result of the polymer mixing improving the tensile strength of the repair material and suppressing shrinkage stress. The chloride ion penetration resistance evaluation showed that when the VAE polymer mixing ratio was 6% or higher, the chloride ion penetration resistance was at the "very low" level. However, when the VAE polymer mixing ratio 3% or less was not satisfied “low”.

https://doi.org/10.11112/jksmi.2024.28.6.142

장종효(Jong-Hyo Jang) ; 이태규(Tae-Gyu Lee) ; 이성혁(Seong-Hyeok Lee) ; 백인혁(In-Hyeok Baek)

Asphalt concrete (AC) tracks are known to reduce maintenance costs and efforts by improving bearing capacity, enhancing the stability and durability of track structures, and reducing vibration and noise. In addition, train operation can be started quickly after asphalt paving is completed, and the track can be quickly restored in the event of major deformation due to derailment, etc., and it is a recyclable material. In this study, the main design parameters, such as dynamic amplification factor, rail deflection, track stiffness, and rail stress, were compared and analyzed between theoretical formulas and measured values based on the measurement results conducted four times per season on the AC track installed on the Icheon-Chungju section of the Central Inland Line, focusing on the superstructure. The research results confirmed that the AC track secures performance and safety that meet domestic and international design standards.

https://doi.org/10.11112/jksmi.2024.28.6.153

홍성욱(Seong-Uk Hong) ; 박준혁(Jun-Hyuk Park)

This paper is a basic study to evaluate the durability and bonding strength by installing a fastening device developed on a wooden deck to improve the durability and bonding strength of the wood deck. Compared to the experiments according to the fastening method, all experiments equipped with the developed fastening device showed an average effect of more than twice as much as the experiments, and as a result of comparing the fracture shape, it was found that lifting, separation, and peeling of the bonding site did not occur, and it was judged to have an integrated shape to suppress deformation, so it was confirmed that the developed fastening device could improve the durability and bonding strength of the wood deck.

https://doi.org/10.11112/jksmi.2024.28.6.163

김동현(Dong-Hyun Kim) ; 정찬진(Chan-Jin Jeong) ; 이승오(Seung-Oh Lee)

This study aims to develop an integrated evaluation model for systematically assessing the aging status of levee facilities and to validate its effectiveness by applying it to a hypothetical levee. The aging assessment of levees is broadly categorized into structural aging assessment and institutional aging assessment. The structural assessment includes factors such as overtopping stability, slope stability, and seepage stability. The institutional assessment focuses on activity state assessment and seepage state assessment, based on safety inspection grades and performance evaluation grades. In this study, equal weights (50%) were assigned to each evaluation category, and the structural aging assessment score and institutional aging assessment score were integrated to derive a comprehensive aging score. By combining structural and institutional aging assessments, this study presents a methodology that allows for a more accurate understanding of the overall aging status of levee facilities. Additionally, future research is suggested to improve the weighting methods for each evaluation category and to validate the model using various real-world cases. It is expected that this will enhance the stability and sustainability of levees and contribute to the establishment of effective maintenance strategies.

https://doi.org/10.11112/jksmi.2024.28.6.173

우한수(Han-Soo Woo) ; 이현호(Hyun-Ho Lee) ; 허무원(Moo- Won Hur)

This study, we design two sky bridge lower connecting devices to be installed on three buildings with a maximum height of 56 stories (200 m).The safety of the sky bridge is examined when an earthquake load occurs by applying a lower connecting device. As a result of examining the safety of the lower seismic isolation device of the sky bridge installed in buildings 101 and 102, the maximum displacement of the seismic isolation device was found to be 67.9 mm. The relative displacement with respect to the lower column of the seismic isolation device was 145.9 mm. In addition, the relative displacement with the upper bridge of the seismic isolation device was 125.9 mm. This result was shown to be safe as it did not exceed the maximum allowable displacement value of 150 mm for the seismic isolation device. As a result of examining the safety of the lower seismic isolation device of the sky bridge installed in buildings 102 and 103, the maximum displacement of the seismic isolation device was found to be 23.4 mm. The relative displacement with respect to the lower column of the seismic isolation device was 78.3 mm. Additionally, the relative displacement with respect to the upper bridge of the seismic isolation device showed a displacement of 65.4 mm. It was found that the maximum allowable displacement of the seismic isolation device did not exceed 150 mm. The seismic isolation devices installed in the three buildings are considered safe against seismic loads.

https://doi.org/10.11112/jksmi.2024.28.6.181

최재경(Jae-Kyeong Choi) ; 양성주(Sung-Ju Yang) ; 김승훈(Seung-Hun Kim)

This study aimed to evaluate the bond strength of small L-shaped steel angles under varying concrete compressive strengths by conducting push-out tests. Specimen’s variables such as the type of angle, cover thickness, bond length, and concrete compressive strength were considered. The experimental results revealed three failure patterns: splitting failure, splitting crack and slip failure, and slip failure. As the bond area increased, the maximum load of specimens increased, but the experimental bond stress showed a slight decreasing trend. Additionally, when the cover thickness increased by 1.25 to 1.5 times, the average bond stress increased by approximately 9.4?21.0%. The average bond stress of the F1 series specimens (fck=31.4 MPa) was 1.14 MPa, with a standard deviation of 0.25 MPa, while that of the F2 series specimens (fck=47.7 MPa) was 1.33 MPa, with a standard deviation of 0.29 MPa. When the concrete compressive strength increased by approximately 51.9%, the average bond stress increased by about 16.7%. Based on the limited experimental results considering variables such as cover thickness, concrete compressive strength, and bond length, this study proposed a bond strength proposed equation consisting of the square root of the concrete compressive strength and a bond stress coefficient(0.1).

https://doi.org/10.11112/jksmi.2024.28.6.191

이의성(Eue-Sung Lee) ; 서지석(Ji-Seok Seo) ; 김윤용(Yun-Yong Kim)

This study was conducted with the purpose of reducing the carbon dioxide emissions of portland cement by utilizing high performance clinker cement (HPCC). The amount of carbon dioxide emitted when manufacturing HPCC was calculated, and the change in carbon dioxide emissions according to the change in the mixing ratio of cement was analyzed. In addition, HPCC-based concrete with the same mix proportions as Ordinary Portland Cement (OPC)-based concrete was manufactured and their properties were compared. As a result of the study, it was found that non-carbonate materials should be included at a weight ratio of approximately 13% in order for the carbon dioxide emissions of HPCC to be equivalent to those of conventional blended cement. The strength development performance of HPCC-based concrete was found to be similar to that of OPC-based concrete.

https://doi.org/10.11112/jksmi.2024.28.6.198

양영섭(Young-Sub Yang) ; 김봉균(Bong-Kyun Kim) ; 이병재(Byung-Jae Lee) ; 김윤용(Yun-Yong Kim)

This study investigated the carbon emissions, compressive strength, and durability of 3DP mortar using various industrial by-products such as blast furnace slag powder, silica fume, and fly ash. The strength test results showed that the higher the mixing ratio of silica fume than fly ash, the higher the strength. Even when 65∼70% of the binder was replaced with industrial by-products, it showed a compressive strength of over 24 MPa. The pH test results showed an overall pH of 9.80∼12.11, showing slightly lower alkalinity than general cement mortar (12.28∼12.33). The chloride ion penetration resistance test results showed that the C-series with high OPC content showed the highest salt resistance. The freeze-thaw test results showed that when blast furnace slag powder was mixed, the relative dynamic elastic modulus was over 80%, which was superior to the mixture without blast furnace slag powder. The amount of CO2 emission from OPC were found to be 98.5?99.1% of that of mortar.