Concrete Compressive Strength Values Research Articles

Contribution to the design of prestressed hollow core purlins without transverse reinforcement

AbstractThe hollow core purlin is a structural element resulting from the sectioning of hollow core slabs into two ribs. This component can be classified as a prestressed hollow core beam without transverse reinforcement. Although this solution offers potential for increasing the productivity of precast concrete element factories, it currently lacks normative guidelines due to the high risk of shear failure. The aim of this study is to highlight an equation to underpin the design of hollow core purlins based on experimental verification. To achieve this objective, six samples of hollow core purlins were analyzed. Initially, the manufacturing characteristics and cross‐sectional geometry of each piece were observed to gather data on the production process. Subsequently, positive bending tests were conducted to characterize stiffness and determine the effective mean tensile strength. Later, shear strength tests were performed to identify the failure mechanisms of the elements. In parallel, the prestressing forces, stiffness, tensile strength, cracking moment, calculated shear strength using the flexural‐shear mechanism, and verification of shear strength due to diagonal tension were computed based on concrete compressive strength values and data provided by the manufacturer. Finally, the experimental values obtained were compared with the theoretical calculated values to establish a correlation that highlights the calculation procedure that best represents the behavior of the studied elements.

Comparing Machine Learning Regression Models for Early-Age Compressive Strength Prediction of Recycled Aggregate Concrete

A branch of artificial intelligence called machine learning is well-positioned as a prediction method that can take into consideration several influencing factors and complex inter-factor connections. Without being specifically trained to do so, these machine learning models have the ability to generalize, predict, and learn from data. Regression theory is a key topic in statistical modelling and machine learning. The main goal of this study is to compare the performance of several popular machine learning regression models for predicting the early-age compressive strength of concretes made from recycled concrete aggregates from a structure that demolished following the Sivrice-Elazig earthquake on January 24, 2020. Early-age concrete compressive strength is even more crucial due to factors like the fact that there are thousands of newly built structures in the aftermath of the earthquake, the quick manufacturing of these structures, and the completion of the project in the lowest amount of time. Determining the early-age concrete strength with high accuracy and in a useful manner is crucial for this reason. Seven different classical machine learning algorithms were employed in this study to achieve all of these goals. Early-age concrete compressive strength values were considered for 1 and 3 days. The relationship between the experimental results and the predicted outcomes of the employed algorithms was investigated, and a thorough comparison of these intelligent regression algorithms was conducted. Within the scope of sustainable development and circular economy goals, it is thought that this article will make significant contributions to the literature in terms of utilizing these waste materials and determining the early-age compressive strengths of the concretes produced with high accuracy.

The Effect of Fineness Modulus of Fine Aggregate on Concrete Compressive Strength

Concrete is the major material used for most civil engineering constructions like buildings, bridges, culvert, rigid road pavement, dam spillway and so on. Concrete is made from a mixture of cement, fine aggregate (sand), coarse aggregate (granite or gravel), and water. The fineness modulus is one of the physical properties of fine aggregates (sand). The Fineness Modulus (FM) of fine aggregates (sand) is obtained from the grading size distribution test as summation of percentage cumulative retained by series of sieves and divided the sum by 100. The fineness modulus of sand differs for each sand quarry. The purpose of this research is to analyze the effect of fineness modulus of fine aggregate (sand) from three different sand quarries on concrete compressive strength. The sand for the study were taken from three quarries (Ayegun, Akufo and Awotan) in Ibadan, Oyo state, Nigeria. The specimens of concrete used in the form of the cube measuring 150x150x150 mm amounted to 36 specimens. The compressive strength of concrete (fc’) targeted is 21 N/mm2 with W/C ratio 0.5. Concrete mix ratio of 1:2:4 was batched by weight. The results showed that the fineness modulus of sand strongly influence the compressive strength of concrete. The classification of sand type is differentiated based on the results of fineness modulus test on each sand sample. Sand fineness modulus (FM) of Ayegun quarry is 2.64 called medium sand (zone 2). Sand fineness modulus of Akufo quarry is 2.35 called mild sand (zone 3), and, sand fineness modulus of Awotan quarry is 1.57 called fine sand (zone 4). Concrete compressive strength values of Ayegun, Akufo and Awotan quarries sand were 21.3 N/mm2, 22.4 N/mm2, and 20.5 N/mm2, respectively. The value of sand fineness modulus does not affect the increase in the concrete compressive strength. The best classification of fine aggregate to increase concrete compressive strength is mild sand (Akufo quarry) and all the sand samples meet the planned concrete compressive strength of 21 N/mm2.

Effect of variations in concrete quality on the crack width in rigid pavement

Cracks pose a significant issue in rigid pavement, leading to substantial damage. The manual mixing and casting of road pavement concrete underscore the importance of concrete quality as a critical parameter. This study investigates crack behavior by varying concrete quality. Loading is performed statically using line loads, shedding light on the impact of concrete quality on crack development. The concrete to be used has a quality fc' of 15 MPa, 25 MPa, and 35 MPa. The fine aggregate used in this study was Lumajang black sand, while the coarse aggregate used was machine crushed stone, and Portland Composite Cement (PCC) was used in all concrete mixes. The reinforcing steel used had a quality fy of 480 MPa, with a reinforcement ratio of ρ=0.010, which was converted to 5-D16 reinforcement. The subgrade density used to support the specimens had a CBR value of 10 %. Specimen dimensions were 2×0.6×0.2 m for length, width, and thickness. Pavement plates, 30 cm thick, were placed on leveled subgrade soil in a steel box set to achieve a 6 % CBR reading. Hydraulic jacks, monitored by a load cell, applied monotonic static loading with 2 kN intervals, reaching a maximum load of 200 kN. Steel tension and plate settlement were measured using a tension sensor and Linear Variable Differential Transformer (LVDT), respectively. A data logger recorded readings, and crack widths were captured by a digital microscope with 0.01 mm accuracy. Experimental results show that low concrete compressive strength values result in larger crack widths, and vice versa. Cracks also occur at earlier loading of concrete quality fc' 15 MPa. In addition, experiments show that the reinforcement stress value has a significant influence on crack width in specimens with low concrete quality

Utilization of Fish Bone Waste as a Substitution of Cement in Concrete

This study aims to determine the effect of using fish bone powder as a substitute for cement and its effect on concrete compressive strength and concrete porosity. Tests for compressive strength of concrete and porosity of concrete were carried out at the age of 28 days using variations of fishbone powder 5%, 10%, 15%, and 20%. The results of testing the compressive strength of concrete at the age of 28 consecutive days were 21,991 MPa, 16,220 MPa, 17,524 MPa, and 12,923 MPa. The largest concrete compressive strength value obtained was a variation of 5% fish bone powder, whereas the porosity values of concrete at 28 days were 11,164%, 12,429%, 11,545%, and 12,764%. Utilization of fish bone waste as a cement substitution can be done in a 5% mixture of fish bone waste. The resulting concrete compressive strength and porosity values are as planned.

A new intelligent sunflower optimization based explainable artificial intelligence approach for early‐age concrete compressive strength classification and mixture design of RAC

AbstractThis study aims to develop a new artificial intelligence model that can produce explainable rules to predict the mix design and early‐age concrete compressive strength classes of recycled aggregate concrete (RAC). Unlike other black‐box machine learning methods and rule‐based algorithms, the study relies on a metaheuristic mechanism for explainability. This metaheuristic mechanism is not used for a traditional parameter optimization, but to automatically extract interpretable and interpretable rules from the experimental data. In the study, 30 series of RACs are produced, and the samples’ 1‐ and 3‐day early‐age concrete compressive strength values are determined. Concretes produced using these strength values are classified. The labels defined for each concrete class are Class A (C 8/10), Class B (C 12/15), Class C (C 16/20), and Class D (C 20/25). The proposed intelligent classification model that consists of rule set automatically produces interpretable and comprehensible rules from data to determine the early‐age concrete compressive strength class and RAC mix amounts. In addition, the proposed method eliminates the black‐box disadvantages of classical machine learning methods with its explainability and interpretability feature. The sunflower optimization algorithm is adapted as the metaheuristic mechanism and a special fitness function and representative solution form are developed for automatic extraction of high‐quality comprehensible rules by simultaneously optimizing many different metrics. This paper is the first interpretable and comprehensible artificial intelligence model attempt used for early‐age compressive strength classification and mixture design of recycled aggregate concrete by balancing and optimizing both the accuracy and explainability. Proposed explainable intelligent classification model is tested against both well‐known state‐of‐the‐art machine learning algorithms and standard rule‐based methods on the produced real data. Promising results in terms of accuracy, precision, recall are obtained along with the explainability feature.

COMPRESSIVE STRENGTH VARIATIONS BY ADDING MARINE SAND AS CONCRETE FINE AGGREGATE IN QUANG NAM, VIETNAM

Recently, considerations in partly replacing traditional concrete fine aggregate contained high river sand is concerned by marine sand to become a concern in Vietnam and the whole world. In the study area of Quang Nam (Vietnam), marine sand is selected to add to concrete fine aggregate because it meets engineering requirements for concrete fine aggregate material about fineness modulus (Ms) and salt content. The main research object is variations of concrete compressive strength (CCS) when adding marine sand to fine aggregate mixes. A proposal of concrete ratio mixes for CCS lab determinations was conducted. Two main non-destructive methods for determining CCS comprise ultrasonic pulse velocity (UPV) and rebound hammer (RH). Results highlight the adding of studied marine sand to concrete fine aggregate mix leads compressive strength of tested concrete block gives unchanged significantly during 90 experimental days in comparison to typical mixing ratio. The effect of marine sand percentage for mixed ratios was mentioned to CCS variations. Series of verification and linear regression is conducted between CCS values in design experimental time (t) to indicate the reliability and strong correlation between them in service of practical engineering aspects.

Real-time in-situ strength monitoring of concrete using maturity method of strength prediction via IoT

The estimated value of concrete compressive strength is vital for early formwork removal, leading to cost benefits for construction projects. The current research proposes a novel and economical IoT based real-time monitoring of strength of concrete during the early stages. The current experimental setup consists of IoT microcontrollers and temperature sensors connected to a cloud-based platform. M20 mix design was used to validate the proposed experimental setup. The maturity relationship between the concrete strength and the temperature was established in the laboratory as per the standards. A prototype slab with an embedded temperature sensor was cast in actual site conditions. Data collected from the temperature sensor from the slab was used to predict the strength of the slab and the results were very closely matched with the actual strength results from the cubes. A cloud-based platform was then used that showed the predicted strength in real-time. The proposed system acts as the case study for further research and development of internet/mobile applications to monitor the early age compressive strength of to aid the project managers to make informed decisions for the early removal of formwork leading to substantial cost benefits in terms of labor work and early completion of activities on a construction project.

Nonlinear 3D Finite Element Model for Round Composite Columns under Various Eccentricity Loads

Composite columns are often used in constructing high-rise structures because they can reduce the size of a building's columns while increasing the usable area in the floor plan. This research aimed to develop a nonlinear 3D finite element analysis model using the ABAQUS, version 6.13-4, of various round composite column designs with varied multi-skin of tubes for solid and hollow columns subjected to various eccentricity loads (90, 180 mm). Extended data to another 12 specimens of composite columns by numerical method, based on six references experimental data of composite columns. The results of ABAQUS data in this study show that; increasing eccentricity for applied loads causes a decrease in loads to fail for composed columns. The ultimate load of hollow composite sections under eccentricity is lower than solid composite sections under different eccentricity loads. Also, the same results indicated fort eccentricity loads. The same results indicated an increased number of steel layers. The stiffness of concrete is greatly influenced by its strength. When the concrete strength rises, the stiffness of the composite column rises as well. The ratios of concrete compressive strength values according to the reference column (CC1S00 with fc’=31.96 MPa) were (-4.4, 3.1, and 6.5) percent for the specimen (CC1S00) with (fc’=25, 35, and 40) MPa, respectively. The method utilized is in the nonlinear analysis, and the finite element results are in good agreement with the experimental results.

Nonlinear 3D Finite Element Model for Square Composite Columns Under Various Parameters

Composite columns are frequently used in constructing high-rise structures because they can minimize the size of the building's columns while increasing the floor plan's usable space. This study aims to create a nonlinear 3D finite element model for square composite columns designed for solid and hollow columns with various multi-skin tubes subjected to loads at eccentricities of (30 and 60) mm, compressive strength, and mesh size using the ABAQUS software. The comparison was based on the experimental data of six references of composite columns. While the compressive strength of concrete increases, the stiffness of the composite column rise. The ratio of concrete compressive strength values for composite column increased by (0, 12.3, 17.8, and 26.7 percent) for (fc'=25, 31.96, 35, and 40) MPa, respectively. The results of the different mesh sizes (20, 40, and 60) mm are showing; The experimental results and the finite element solution developed using the (20 X20) mm element correspond well. The nonlinear finite element analysis method was used, and the finite element outputs results were confirmed to be in favorable agreement with the experimental data

Determining Concrete Structure Condition Rating Based on Concrete Compressive Strength

The need for concrete condition assessment for existing buildings increases because of high disaster vulnerability levels, as well as a large number of buildings that have reached their age of use. Currently, there is not any standard reference for assessing concrete condition rating yet, so a concrete condition assessment method that can be measured quantitatively needs to be developed. The developed concrete condition assessment method combines concrete condition assessment based on visual inspection and testing. Assessment measures start with an assessment of visual inspection results, which is continued with concrete compressive strength testing. This article contains a concrete condition assessment based on concrete compressive strength testing. This method determines the concrete condition rating scale using five condition ratings as a reference for building condition assessment. The limit value of each condition rating is taken from concrete compressive strength values that are structurally sufficient, according to the structural concrete requirement code for buildings. Concrete compressive strength values have resulted from non-destructive tests and destructive or loading tests. Building condition rating (BCR) value determination factors in the effect of structure element damage towards building structure and concrete testing result accuracy rating, and also can decrease inaccuracy towards concrete quality condition rating determination on scale limit values, and minimize error risks in determining damage condition rating. The resulting method has the advantage of assessing structure element condition rating and building condition rating (BCR) that can be measured quantitatively, has five assessment scale ratings that can portray building conditions having to be demolished, and calculates structure element critical weight.

Experimental Study on the Size Effect on the Probability Distribution of Concrete Compressive Strength

Understanding the size effect on the probability distribution of concrete compressive strength is critical to accurately determining its probability distribution and to correctly calculating reliability. Compressive strength tests were performed on concrete cubic specimens with side lengths of 70 mm, 100 mm, and 150 mm, respectively. The Kolmogorov‐Smirnov test results revealed that concrete compressive strength of each specimen size followed a normal probability distribution; that is, a change in specimen size did not affect the type of probability distribution. The point and interval estimates of the mean and standard deviation of concrete compressive strength showed that both the mean and standard deviation decreased, and the latter decreased to a greater extent with an increase in specimen size. The calculation results show that the standard value of concrete compressive strength also has a significant size effect, but the standard value increases with an increase in specimen size, which is opposite to the change pattern of concrete compressive strength mean and standard deviation. Finally, a reliability analysis was carried out using the compressive strength of a cubic concrete specimen with a size of 150 mm as an example, and the probability distributions for different specimen sizes were found to have a great influence on the reliability of the calculation results. Therefore, it is important to account for the size effect on the probability distribution of concrete compressive strength in practical engineering.

PEMANFAATAN LIMBAH SERAT TALI BENESER DALAM MENINGKATKAN KUAT TEKAN DAN KUAT TARIK BELAH BETON

This study aims to determine the utilization of fiber rope waste (strapping band) in increasing the compressive strength and tensile strength of concrete with fiber cross-section size of 2-3 mm and length of 60 mm with variations in the addition of 0 kg/m3, 0,25 kg/m3, 0,5 kg/m3, 0,75 kg/m3, and 1 kg/m3 concrete .the compressive strength of the plan is 30 MPa. The specimen is cylindrical size 150 mm x 300 mm with concrete making planning refers to SNI 03-2834-2000. The results with the addition of rope fibers (strapping band) shows the compressive strength of variations 0 kg/m3, 0,25 kg/m3, 0,5 kg/m3, 0,75 kg/m3, and 1 kg/m3 respectively are 12,55 MPa, 8,87 MPa, 16,608 MPa, 11,418 MPa and 12,644 MPa with the optimum value of concrete compressive strength of 16,608 MPa at variations of the addition of 0,5 kg/m3of fibers. Thus from all the compressive strength values obtained, there are no concretes that reaches the compressive strength of the plan. Whereas the results of tensile strength test are 1,42 MPa, 0,8 MPa, 1,35 MPa, 1,06 MPa and 1,13 MPa respectively with the optimum tensile strength value of 1,53 MPa in variations of addition of 0,5 kg/m3 fibers.

Bacterial from wawolesea hot springs: crack sealing application to concrete

Concrete is one of the most widely used construction materials for infrastructure, but concrete has the disadvantage of being easy to crack. One of the factors that influence concrete cracks is rain water, because water can enter and seep into the pores. Several studies have been carried out to overcome the cracking of concrete structures; one of them is the addition of bacteria that have calcium carbonate precipitating activity. Calcium carbonate from bacterial metabolism can closed on cracked concrete surfaces. This method is commonly called Microbial Induced Calcite Precipitation (MICP). The source of bacteria in this study is bacteria at Wawalosea hot springs from the limestone mountain. The research is healing of cracks in concrete compare by bacteria MICP and MICP immobilization using alginate-chitin. The results showed that the concrete made with the addition of MICP isolates as much as 1.6x108 cells / mL had a greater compressive strength than the concrete without the addition of isolates. The value of compressive strength and absorbency of concrete water with the addition of MICP isolates has a compressive strength of 25.78 Mpa and addition imobilization MICP has 18 Mpa. So when compared to concrete without the addition of isolates and concrete with the addition of MICP isolates, the value of concrete compressive strength occurred at 100%.

Incorporation of Wheat Straw Ash as Partial Sand Replacement for Production of Eco-Friendly Concrete

The depletion of natural sand resources occurs due to excessive consumption of aggregate for concrete production. Continuous extraction of sand from riverbeds permanently depletes fine aggregate resources. At the same time, a major ecological challenge is the disposal of agricultural waste ash from biomass burning. In this study, an environmental friendly solution is proposed to investigate the incorporation of wheat straw ash (WSA) by replacing 0, 5, 10, 15, and 20% of sand in concrete. Characterization results of WSA revealed that it was well-graded, free from organic impurities, and characterized by perforated and highly porous tubules attributed to its porous morphology. A decrease in fresh concrete density and an increase in slump values were attained by an increase in WSA replacement percentage. An increasing trend in compressive strength, hardened concrete density, and ultrasonic pulse velocity was observed, while a decrease was noticed in the values of water absorption with the increase in WSA replacement percentages and the curing age. The WSA incorporation at all replacement percentages yielded concrete compressive strength values over 21 MPa, which complies with the minimum strength requirement of structural concrete as specified in ACI 318-19. Acid resistance of WSA incorporated concrete improved due to the formation of pozzolanic hydrates as evident in Chappelle activity and thermogravimetric analysis (TGA) results of WSA modified composites. Thus, the incorporation of WSA provides an environmentally friendly solution for its disposal. It helps in conserving natural aggregate resources by providing a suitable alternative to fine aggregate for the construction industry.

Pengaruh Variasi Suhu Air 27ºC, 37ºC, 47ºC Pada Campuran Beton Terhadap Nilai Kuat Tekan Beton Struktural

Tujuan dari penelitian ini adalah untuk melihat pengaruh variasi suhu air dengan variasi suhu air 27ºC, 37ºC, 45ºC pada campuran beton terhadap nilai kuat tekan beton struktural. Penelitian ini mengggunakan benda uji berbentuk silinder diameter 150 mm dan tinggi 300 mm. Pengujian benda uji dilakukan pada umur 3 hari, 7 hari, 14 hari, dan 28 hari. Berdasarkan hasil pengujian benda uji diperoleh nilai kuat tekan pada umur 3 hari dengan suhu air 27ºC sebesar 14,132 MPa, 37ºC sebesar 19,496 MPa, 47ºC sebesar 21,554 MPa. Hasil pengujian pada umur 7 hari diperoleh nilai kuat tekan dengan suhu air 27ºC sebesar 19,817 MPa, 37ºC sebesar 22,471 MPa, 47ºC sebesar 25,822 MPa. Hasil pengujian pada umur 14 hari dengan suhu air 27ºC sebesar 27,090 MPa, 37ºC sebesar 28,556 MPa, 47ºC sebesar 28,973 MPa. Hasil pengujian pada umur 28 hari kuat tekan beton dengan suhu air 27ºC sebesar 30,246, 37ºC sebesar 31,250 MPa, 32,149 MPa. Suhu air normal 27ºC yang digunakan sebagai acuan untuk melihat pengaruh pada nilai kuat tekan beton. Berdasarkan studi ini, penggunaan air pada campuran beton dengan suhu 37ºC dan 45ºC mempengaruhi nilai kuat tekan beton.
 Kata kunci: Beton Struktural, Variasi Suhu Air , Kuat Tekan.

INOVASI BETON RAMAH LINGKUNGAN

In this study the author take Fly Ash and Powder Glass as an added ingredient in the concrete mix. This research intend to know the effect of Fly Ash and Powder Glass on K-300 concrete compressive strenght.This study uses cube-shaped specimens with the siza of 15 x 15 x 15. The total of test specimens in this study as much as 45 sample, each 9 seal of test specimens in 5 condition that is normal, concrete + fly ash 5% + glass powder 18%, concrete + fly ash 5% + glass powder 21%, concrete + fly ash 5% + glass powder 24%, concrete + fly ash 5% + glass powder 27%.After concrete compressive strenght test, the concrete strength og the concrete at age 3, 7 and 28 days with normal condition at 3 days age aqual to 139.26 Kg/Cm2, at age 7 day equal to 202.17 Kg/Cm2 and age 28 day of 307.01 Kg/Cm2. And the value of compressive strength of concrete characteristic with the use of Fly Ash 5% + glass powder 18% has the highest value of concrete compressive strength that is at 3 days age of 151.13 Kg/Cm2, 7 day age equal to 21175 Kg/Cm2 and age 28 is 312.81 Kg/Cm2 . These result exceed the copressive strength values of normal concrete characteristic and show that fly ash and glass powder can increase the compressive of the concrete.

Value of concrete compressive strength with variation of candlenut shell applicated to plate on a non-destructive test using UPV

Concrete began to use substitute materials to reduce the brittle nature. Substitution material is material that can replace concrete material both coarse aggregate, fine aggregate, and cement with other materials, such as Portland cement with steel slag, broken stone (coarse aggregate) with pumice and other stones. One of the benefits of the concrete material substitution method is that it can use organic waste. Organic waste can be in the form of residual production or usage, one of which is the candlenut shell which is a waste of candlenutThe candlenut shell is a new potential that can be developed and utilized even greater. Of course It can increase the economic value of the candlenut shell which has only been known as a waste material from the candlenut. The composition of the candlenut shells are CaO, SiO2, Al2O3, MgO, H2O, Fe2O3. When all reacts, there will be residual SiO2 that has not yet reacted to form a silica derivative reaction with CSH-2 gel resulting in a denser CSH-3 gel, which will increase the cement paste and aggregate. The purpose of this discussion is to determine the compressive strength value of candlenut shell concrete at 0% and 30% variation on the plates using Ultrasonic Pulse Velocity (UPV) at 28 days. The method used is experimental by testing samples / specimens in the form of reinforced plate size of 50cmx25cmx12cm with wet curing and dry curing methods with a variation in age of 28 days. Concrete compressive strength testing is done using UPV tools. The results of this discussion are the compressive strength of 30% candlenut shell variations on the application of the plate shows that the quality of the concrete produced in the wet curing reaches 18 MPa or equivalent to the quality of the K 225 concrete and the dry curing is only 14 MPa or equivalent to the quality of K175, while the variation Candlenut shells 0% (normal concrete) reach 28 MPa on wet curing and 24 MPa on dry curing. This shows that the plate with a variation of 30% candlenut shells are still able to achieve concrete quality II for use in structural work.

STUDI PENAMBAHAN SUPEPRPLASTCIZER PADA KUAT TEAN BETON DENGAN VARIASI FAS 0,4 – 0,5 MENGGUNAKAN AGREGAT KASAR YANG DI PECAH (SPLIT)

This study aims to determine the effect of superplasticizer usage on concrete compressivestrenght with variation of water cement ratio using subdivided crude aggregates (split).This research cylindrical test object with diameter 15 cm and height 30 cm. Compressivestrength concrete design fc’ 35 MPa, with variation of water cement ratio W/C 0,4; 0,45; 0,5 andusing Superplasticizer Sikament LN materials 0,5% of the weight of cement and slump value 12 ± 2cm.The result of research showed an increase the value of concrete compressive strength withthe addition of superplasticizer. The average of concrete compressive strength without the addition ofsuperplasticizer and variation of water cement ratio W/C 0,4; 0,45; 0,5 at 28 days in a row is 36,14MPa, 34,73 MPa, 29,82 MPa. While the value of concrete compressive strength with the addition ofsuperplasticizer increase to 39,73 MPa, 37,18 MPa, 31,23 MPa.

Control of Quality Concrete Base on Curing Methods

This concrete maintenance procedure is very difficult to carry out in the field or construction project, because of the influence of the volume of concrete in a large field, also very high mobility. The purpose of this study is to analyze maintenance-based concrete quality control in construction projects that are in accordance with SNI-2493-2011 standards. The research method carried out by the experimental method, the test object used was cylindrical with a diameter of 15 cm and a height of 30 cm, with fc 25 MPa plan. The treatment method is to cover the concrete using wet „goni‟ sacks and sprinkling the concrete using water, with variations of treatments for 1 day, 3 days and 7 days such as the time of treatment in the construction project. as a concrete quality control with a method of soaking concrete for 28 days according to SNI-2493-2011. Test Results The value of concrete compressive strength that reaches only concrete control compressive strength of 25.97 MPa or greater than f’c of 3.88% and for the treatment method in the field no one reaches the plan compressive strength value. However, from the treatment method in the field, the optimum compressive strength is the maintenance method to cover concrete with „goni‟ sacks for 7 days at 24.11 MPa. In general, concrete treated in the field with a maintenance method closes the concrete using „goni‟ sacks the compressive strength value is higher than the concrete sprinkling treatment method.