Hard Concrete Research Articles

Analisis Kelayakan Kualitas Material Batu Pecah Dan Pasir Asal Kelurahan Wandoka Kecamatan Wangi-Wangi Kabupaten Wakatobi Sebagai Bahan Konstruksi Gedung

Concrete is a construction material consisting of cement, fine aggregate, coarse aggregate which is mixed and added with sufficient water to form a dough which then hardens into hard concrete. This study aims to determine technical feasibility, the cost and the difference to the unit price based on the 2021 Regent's Regulation and to analyze the unit cost of construction of local Wakatobi materials and materials outside Wakatobi based on Analisa Harga Satuan Pekerjaan (AHSP). The method used in this study to determine the compressive strength of concrete refers to SNI 1974; 2011 and carried out observations and measurements in the laboratory with 60 specimens in the form of a cylinder with a diameter of 10 cm and a height of 20 cm with a concrete age of 28 days for each mixture variation. The results of the study obtained the compressive strength of aggregate variations on 100% Moramo coarse aggregate on crushed stone and sand with several variations. Comparison of the unit price of the Wakatobi local fine aggregate material with the outer Wakatobi fine aggregate material is 32.40% higher, the Wakatobi local coarse aggregate material unit price and the outer Wakatobi coarse aggregate material unit price is 52.17% higher. The construction unit cost for making 1 m3 of concrete using local Wakatobi materials is Rp. 1,916,756, and the construction unit cost for making 1m3 of concrete using non-wakatobi materials is Rp. 2,678,889. With a large construction unit, making 1m3 of concrete using external Wakatobi materials is 28.45% higher.

Soft Power in Hard Concrete: the Berlin Congress Hall, the Cold War and the Building of Transatlantic Relations

Summary The opening of the Congress Hall in Berlin-Tiergarten in 1957 took place during the heyday of the Cold War. Designed by American architect Hugh Stubbins, the building became a focal point in East–West confrontations. Against this backdrop, the article explores the role of architecture in national soft power by taking the example of the Berlin Congress Hall. Commencing with a discussion of architecture as a component of soft power along five criteria, it goes on to examine the planning of the Congress Hall and the significance of its unique design vocabulary. The article concludes that the building, strategically located near the sector borders separating East and West, represents a concrete embodiment of US soft power. Although not an official representational building, the Congress Hall has thus served as a political, cultural and ideational ‘embassy’ of the United States and a major building block in German–American relations up to the present.

Effect of Marble Dust Powder on the Properties of Fresh and Hard Concrete

The goal is to investigate the potential for employing byproducts from various industrial processes in the creation of ground-breaking mortar and concrete. The dust produced during the marble-cutting operation is put to good use. Different percentages of this garbage were recommended to be used in conjunction with or in place of cement in the making of concrete. The research looked into the possibility of using marble dust, which is produced during the shaping of marble blocks, as a cementitious material in concrete. In areas where they are readily available and can reduce construction costs, the study found that dust from marble slabs could be employed as a cementitious material in concrete mixtures. The discarded marble dust is mixed with cement in proportions of 5, 10, 15, and 20% of the standard concrete mix. Both the fresh and hardened characteristics of the produced combinations were investigated. Compressive and tensile strengths were measured after being cured for varying periods of time, both when marble dust was used as a partial replacement and when it was not.

Effect of Accelerators on High Early Strength Concrete (HESC) Using High Volume Fly Ash

Applying large quantities of fly ash for the production of High Early Strength Concrete (HESC) is a challenge for researchers in the utilization of quality, inexpensive, and environmentally friendly materials. A high volume of fly ash in concrete, however, reduces the initial compressive strength of the concrete. For this reason, it is necessary to use admixture additives in the concrete mixture to get the expected performance. This research seeks to identify the optimal HESC mix design using fly ash 50% of the total cementitious by adding a superplasticizer and accelerator to obtain a high initial compressive strength. Three variations of HESC, namely HESC-12, HESC-14, and HESC-16, were made using a superplasticizer and accelerator with different doses. Each variation uses 12 liters of superplasticizer and different accelerator volumes: 12 liters, 14 liters, and 16 liters. Specimen testing was carried out on fresh and hard concrete. Fresh concrete was subjected to a slump test, whereas hard concrete was subjected to compressive tests at 18 hours, 24 hours, 3 days, and 28 days of age. The average slump flow values for HESC-12, HESC-14, and HESC-16 (cm) were 78, 79.5, and 80, respectively, demonstrating that all HESC samples are classified as self-compacting concrete (SCC). According to the results of density tests conducted on all specimens ranging from 2461 to 2538 kg/m3, all specimens are included in the category of normal-weight concrete. Within the range of 29.8 to 35.3 MPa for the initial compressive strength of HESC at 24 hours of age, it can be concluded that all HESC specimens fulfill the criteria for high early-strength concrete. The addition of the right type and dosage of chemical admixture is a solution to overcome the weakness of applying fly ash in high-early-strength concrete.

Increasing the Hydration Activity of Tricalcium Silicate by Adding Microdispersed Ettringite as a Nucleating Agent.

Tricalcium silicate (C3S) as a binder material has a decisive influence on the processes of hardening and strength gain of cements and concretes. One of the promising directions is the introduction of dispersed additives into cement mixtures, which allow micro-level control of the composition of hydration products and change the dynamics of the structure formation of cement stone. In this paper, the effect of a microdisperse ettringite additive on the kinetics of the hydration and hardening process of tricalcium silicate was studied. It was shown that ettringite crystals selectively adsorb Ca2+ and OH- ions from a saturated solution of calcium hydroxide, which contributes to the formation of hydrosilicate nuclei on their surface during cement hydration. Hydration of C3S in the presence of ettringite proceeds more intensively; the addition of ettringite contributes to an increase in the content of calcium hydrosilicates in hydration products at the initial stage of the process. Addition of 10 wt.% ettringite to C3S reduces the induction period of the beginning of the main phase of heat release by around two times and increases the amount of heat released on the 1st day of hydration by 15% compared to the control sample. According to electron microscopy data, it was found that during the first hours of hydration of modified C3S, a significant number of nuclei of fibrous particles of calcium hydrosilicates with sizes of 0.2-2 microns were formed on the surface of ettringite crystals. According to the results of kinetic modeling of the setting process of cement pastes using the Avrami-Erofeyev model, it was shown that in the presence of the addition of microcrystals of ettringite, the setting rate is characterized by a slowdown in nucleation, whereas for a sample without an additive, this process proceeds with an acceleration of the formation of solid-phase nuclei. Based on the comparison of kinetic results and mechanical measurements, it is concluded that needle crystals of ettringite during C3S hydration and cement stone hardening are preformed centers for the growth of hydrosilicate nuclei, and they also act as a reinforcing filler, increasing the bending strength of modified samples. The results of the work can be used in practice in the development of methods for controlling the processes of hydration and hardening of cements, as well as for controllable structure formation of cement stone which is important in particular for 3D printing of building products and constructions.

New Hominin calvaria discovery from Grenzbank Layer of Sangiran Dome (Java, Indonesia): The last archaic Homo erectus lived in Java

Sangiran Dome in Central Java, Indonesia, is the most significant hominin site in Island Southeast Asia. Up to now, there are more than a hundred of Homo erectus individuals recovered from the site, and the most recent finding is an unpublished posterior part of Bjg 1602 skullcap, discovered by a local people in 2016 from the surface of Kali (River) Bojong, out of stratigraphical context. But, based on the hard concretion well attached on the fossil, consists of coarse conglomeratic sand and pisoid-limestones – defined for the first time by G.H.R. von Koenigswald as the grenzbank layer – this skullcap is interpreted originally from this layer. Stratigraphically, the layer is situated between the black clay of Pucangan Formation of Lower Pleistocene and the fluvio-volcanic sands of Kabuh Formation of Middle Pleistocene. Thus, this layer was deposited on the Sangiran site some 0.9–0.8 ma, which is the minimal age of the skull respectively. This paper aims to identify the possibly position of the specimen and its context to the Homo erectus evolution in Java. The specimen was analysed by applying the morphological and metrical descriptions of the external characters. Then, a comparative study to other African (n=5), Asian (n=7), and Javan Homo erectus (n=23) was conducted by using univariate and bivariate statistical analysis, in order to place the specimen into evolutionary perspective. The result shows that Bjg 1602 skullcap is very closed in morphology and size to the robust Sangiran 4 skullcap (firstly known as Pithecanthropus robustus), which is one of the robust Homo erectus members from the Early Pleistocene between 1.6 to 1.2 ma. Thus, it could be concluded that the specimen of Bjg 1602 represents the last survival of robust Homo erectus in Java during the early of Middle Pleistocene, some 0.9 ma.

Study on stress variation law of hard concretion coal under the action of pick based on DYNA

Modeling and simulation of pick cutting hard concretion coal process are taken as a key link to analyze the stress variation law. To this aim, the properties of hard concretion coal in the target mining area were tested. Related model with high-quality common grid was generated using the mapping method through Hypermesh. the coal breaking process was performed using LS-DYNA, and the stress variation law of coal and hard concretion was analyzed. The results showed that the closer the action position to the middle point of long axis of hard concretion, the greater stress peak would be generated, stripping of the pick occurred when it acted on the 2/5 and 1/2 positions of the long axis. Using similarity theory, the model of hard concretion coal was made and the pick cutting experiment was performed. Compared with simulation torque result, the correctness of modeling and simulation has been verified.

Analysis on the influence law of traction speed on the cutting performance of coal containing hard concretion

Due to the great differences in mechanical properties between hard concretion and coal, the shearer drum cutting coal and rock containing hard concretion will inevitably lead to a series of problems, such as severe load impact, increased cutting specific energy consumption and low coal loading efficiency. Taking the cutting part of a thin coal seam shearer in service in the target mining area as the prototype, the mechanical models of shearer drum and rocker arm are established by using UG, and the discrete element model of coal wall with hard concretions is built by importing it into EDEM. The influence law of traction speed on coal loading rate, drum load and cutting specific energy consumption is analyzed, and the corresponding fitting relationship function is obtained. Taking the traction speed as the design variable, and the drum load, cutting specific energy consumption and coal loading rate as the comprehensive indicators, a multi-objective optimization function is established. The optimal solution is obtained by using NSGA II optimization algorithm, and the accuracy of the simulation is verified by experiments. This method has certain engineering significance for the reasonable selection of shearer traction speed.

Study of concrete mix by adding Dolomite in conventional concrete as partial replacement with cement

Massive quantities of dolomite wastes are produced every year in under-developing nations like India. Disposal of dolomite waste is a very severe problem as it requires huge space for its disposal and very small quantity of waste is recycled or reused. This experimental study has been carried out to assess the effect of partial replacement of coarse aggregate by dolomite waste on workability, compressive strength and flexural strength of concrete. In this paper by using waste dolomite in concrete as partial replacement in various percentages with coarse aggregate. For making M25 grade using IS: 10262–2019.Objective of study to analyzing physical property of fresh concrete that is workability & compressive strength, flexural strength of hard concrete in M25 by adding dolomite as partial replacement in conventional concrete mix with 5%, 10%, 15%, 20%, 25%, and 30% The cube samples of M25 grade concrete mix are cast for study purpose. The important aim of this paper is to utilize the dolomite waste in concrete and to make the construction ecofriendly and to make concrete work economic to some extent. It is also essential to protect the natural raw resources like stone aggregates, sand etc. Therefore, the sustainable concept was introduced in modern construction industry.

S3547 Cellulase With Prokinetics Is an Effective Dissolution Therapy for Gastric Phytobezoars

Introduction: Gastric phytobezoars are hard concretions of ingested vegetable/food matter in the stomach. They can significantly impair mucosal visualization during esophagogastroduodenoscopy (EGD). In the absence of outlet obstruction, dissolution therapy is recommended as a first step whilst evaluating for underlying causes. Different dissolution therapies for bezoar have been described. Cellulase, although first described in 1980’s has not been systematically examined and whether combined therapy with prokinetics is more effective is unknown. We describe two patients with large gastric phytobezoars found on EGD and successfully treated with cellulase plus adjuvant azithromycin for 5 days. Case Description/Methods: Case 1: A 37-year-old Caucasian woman with type 2 diabetes mellitus (DM), gastroparesis and obesity presented with a 2-year history of worsening GERD, dyspepsia, early satiety and Gastroparesis Cardinal Symptom Index (GCSI) of 24. EGD revealed a large phytobezoar, occupying 60% of stomach (Fig. 1a). She was treated with Cellulase 5 g dissolved in 200 ml of water, daily for 5 days on an empty stomach, and azithromycin 125 mg liquid bid for 3 weeks. She reported significant symptom improvement in 1 week. Repeat EGD after 2-3 weeks showed normal stomach with no bezoar (Fig. 1b), and GCSI improved to 18. Case 2: A 64-year-old Caucasian woman with Type 2 DM and gastroparesis presented with worsening nausea, vomiting, early satiety and GCSI of 22. Examination noted mild epigastric fullness with tenderness and succussion splash. EGD noted a large gastric bezoar occupying the 75% of stomach. She was treated with aforementioned regimen. EGD after 2 weeks was normal with no bezoar (Fig. 1c), and GCSI improved to 16 (Figure). Discussion: Gastric bezoars are rare with an estimated incidence of 0.3% on EGD. Risk factors include gastric dysmotility, gastric outlet obstruction, anticholinergic agents/opioids or psychiatric problems. They can be asymptomatic or cause abdominal pain, nausea, vomiting or early satiety. Agents used for chemical dissolution therapy (CDT) with varying results include cellulase, carbonated drinks, papain and acetylcysteine. Both of our patients had gastroparesis with poorly controlled DM and intolerance to metoclopramide. Possible risks of CDT include possible small bowel obstruction from partially dissolved bezoars. Combination therapy with Cellulase (5G), and Azithromycin (125 mg liquid bid, prokinetic) was safe and effective therapy for gastric phytobezoars without luminal obstruction.Figure 1.: 1. Endoscopic images (Patient 1) showing large phytobezoar (a) and repeat EGD in 2 weeks showing normal stomach after dissolution therapy (b). Normal EGD (patient 2) after dissolution therapy (c).

Boundaries and lithofacies of the Kati Formation (SW Perak, Peninsular Malaysia)

Very few geological research has been undergone on the Kati formation due to its scarcity of natural outcrops and complexity. The heavily weathered and limited number of natural outcrops available around the areas of Bandar Seri Iskandar and Parit (Perak) may help to define the Kati Formation in a more clear way. After recent human construction activities, more exposures can be studied, which makes easier the process of gathering geological information. The Kati Formation inspires quite a few questions to the scientific community, such as the source of the iron oxide extensively found on it and the processes that turned a softer shale into hard concretions, the presence of trace fossils as the only palaeontological evidences preserved in this heavily replaced rock unit, and the age of the overlying quaternary deposits, which is a key for understanding, in turn, the succeeding diagenetic processes. The objective of this research is to better define the Kati Formation in relationship to their associated quaternary materials, Mesozoic granites and metamorphic rocks, all by using classical stratigraphic methods first.

Compressive Behavior of Oil Shale with Calcareous Concretion: Parametric Study

The non-uniformly distributed calcareous concretion among the oil shale in the Junggar basin of China has led to the difficulty in achieving the slope stability. This paper presents the numerical simulation of the behavior of oil shale with calcareous concretion via the Particle Flow Code (PFC2D) program based on the trial experimental test results. The critical parameters investigated in this research covered the size, distribution, strength, and number of the calcareous concretion. The following conclusions can be drawn based on the discussions and analysis: (1) the hard concretion always results in the high compressive strength of the specimen compared with that without concretion; (2) when the radius of the concretion size raised from 2.5 mm to 20 mm, the peak strength of tested specimens is approximately 50 MPa, whereas, the specimen with large concretion is much more ductile under compression; (3) the compressive behavior of tested specimens is similar even when the position of the concretion is variable; and (4) different from the specimens with only one concretion, these specimens contained two concretions featured with the double “X” failure mode. Meanwhile, the peak strength of the specimens with two hard concretions is about 2.5 times that of its counterparts with two soft concretions. The numerical simulation results are meaningful in guiding the design and analysis of the oil shale slope with the concretion.

Enhancing Slump Flow, Specific Gravity, and Compressive Strenght Material Properties of Self Compacting Concrete (SCC) with Glass Waste Powder

Self Compacting Concrete (SCC) is the latest and advanced technology in the field of concrete technology. SCC is an innovative type of concrete, one of which has properties flowable. In this study, one of the innovations in the use of glass bottles as a substitute some cement for SCC. This research was conducted to determine the effect of glass waste powder as partial substitute for cement on slump flow, specific gravity, and the compressive strength of concrete aged 14 days SCC. The mix design used was Okumura’s Simple Mix Design [1], water-per-powder ratio 0.35, and dosage superplasticizer 1%. Variation of glass waste powder 0%, 5%, 10%, 15%, 20%, 25%, and 30% of the weight of cement, the size of the waste glass powder is through the filter no. 100 and stuck in the filter no. 200. The test object in this study uses a cylinder with diameter 15 cm and height 30 cm. The flowability test is carried out when the concrete is fresh. For hard concrete, specific gravity and compressive strength tests are carried out at the age of 14 days. The result of replacing glass waste powder as a substitute for some cement has a significant effect on the slump flow value of 85%. Slump flow in fresh concrete mixture with various glass waste powder 5%, 10%, 15%, and 20% reach the standard [2]. Replacement of glass waste powder as a substitute for part of cement has a significant effect on the specific gravity concrete amounting to 69.6%. Specific gravity concrete in this study fulfills the requirements for structural normal specific gravity[3]. On the compressive strength of concrete aged 14 days, glass waste powder has a significant effect of 86.2%. Compressive strength has a maximum compressive strength of 35.322 MPa, with an optimal percentage of glass waste powder as a substitute for partial cement is 10.464%.

A theatrical double-faced mask preserved at the Museum of Lipari (Messina): study and 3D reconstruction through portable equipment

<p class="VARKeywords">The new tools for 3D survey and modelling (as portable scanners and software packages), often in combination with diagnostics, are nowadays able to provide indispensable elements for the study of archaeological artefacts; their applications to museum’s heritage can be also useful to integrate the traditional graphic documentation and contribute to enhancement and dissemination. This paper shows the benefit of using the aforementioned tools to study the peculiar clay mask No. 11114-E, discovered in 1973 in the Greek necropolis of Lipára, inside tomb No. 1558. The specimen, now exhibited in the Classical Section of the Aeolian Museum, is considered unique both in the Aeolian Islands and in the ancient Greek world, as it is the only one merging two half faces attributable to different characters. This feature, unknown at the time of discovery, has been highlighted in 2018, thanks to a restoration intervention by which a hard concretion layer covering a large portion of the mask surface was removed, bringing to light a smiling young half-face next to an old one with Silenic features. In 2019, the mask was surveyed in situ through a portable and performing laser-scanner arm (the QuantumTM FaroArm by FARO) to produce a high-resolution 3D model useful to enhance the reading of the two halves (not evident enough, due to its state of preservation). The data processing was performed using the Geomagic Wrap software, able to align and merge multiple scans into a single model and to export results in multiple formats, easily shareable and viewable in free software or via the web. Finally, thanks to this method, the successful generation of a digital replica was performed; the resulting replica is useful for dissemination and as a support for the hypothetical reconstruction of the two prototypes taken as models by the craftsman who created the mask.</p><p><strong>Highlights:</strong></p><ul><li><p>A 'mobile laboratory’ consisting of portable equipment has been set up to perform 3D metric surveys on a selection of artefacts preserved at the Museum of Lipari.</p></li><li><p>By means of an ultra-precision laser-scanner arm, a 3D survey on a miniaturistic double-faced mask, belonging to the classical theatrical terracotta, has been performed.</p></li><li><p>A geometrically accurate and realistic 3D final model has been created. This helped the study and reconstruction of the two characters composing the mask.</p></li></ul>

The Impact of Guinea Corn Husk Ash as an Admixture for Crack Control in Concrete

Guinea corn husk, a post-harvest agricultural waste common in Northern Nigeria is often heaped up constituting environmental nuisance. Guinea Corn Husk Ash (GCHA) is an incinerated by-product of it. In this experimental investigation, it was used to replace cement in concrete at levels of 0%, 5%, 10%, 20%, 30% and 40% by weight. The sample cubes were casted and cured for 3, 14, 28 and 56 days before crushing. Before then, the chemical constituents of the GCHA were determined from an X-Ray diffraction analyzer. The oxides found in the ash included SiO2 (85.4%), K2O (4.01%), Fe2O3 (0.64%), CaO (2.04%) and NaO2 (0.98%). SO3 and AI2O3 were not detected. The combined percent of SiO2, Al2O3 and Fe2O3 of 86.04% is above the 70% benchmark for a pozzolana material. Also, SO3 and NaO2 fell below the maximum allowable values of 4% and 1.5% respectively. The fresh concrete had slump values that ranged from 11mm for 0% cement replacement to 3.6mm for 40% replacement. The hard concrete had the highest compressive strength value of 23.67 N/mm2 for plain concrete and 49.3 N/mm2 at 5% GCHA replacement level. All were at 56 days of curing, satisfying quality for heavy load bearing. Beam samples cured for 3, 14, 28 and 56 days were subjected to flexural tests until they developed cracks. The cracks were measured for lengths (CRL) and width (CRW) for different replacement levels and curing days with a crack measuring microscope. The results show that, at 14days curing, there is a trend in the crack values’ reduction for the hardened GCHA concrete. This trend is also marginally seen for the 28 day cured samples, particularly at up to 20% replacement levels. The decrease in crack values were up to 17.2% and 2091% for CRL and CRW respectively. However, there were no significant crack controls with samples of higher replacement levels and those cured for 3 and 56 days. GCHA concrete can therefore be used to for heavy load bearing structures and for crack control at 5 – 20% replacement levels when cured for 14 days and 38 days.

The Impact of Guinea Corn Husk Ash as an Admixture for Crack Control in Concrete

Guinea corn husk, a post-harvest agricultural waste common in Northern Nigeria is often heaped up constituting environmental nuisance. Guinea Corn Husk Ash (GCHA) is an incinerated by-product of it. In this experimental investigation, it was used to replace cement in concrete at levels of 0%, 5%, 10%, 20%, 30% and 40% by weight. The sample cubes were casted and cured for 3, 14, 28 and 56 days before crushing. Before then, the chemical constituents of the GCHA were determined from an X-Ray diffraction analyzer. The oxides found in the ash included SiO2 (85.4%), K2O (4.01%), Fe2O3 (0.64%), CaO (2.04%) and NaO2 (0.98%). SO3 and AI2O3 were not detected. The combined percent of SiO2, Al2O3 and Fe2O3 of 86.04% is above the 70% benchmark for a pozzolana material. Also, SO3 and NaO2 fell below the maximum allowable values of 4% and 1.5% respectively. The fresh concrete had slump values that ranged from 11mm for 0% cement replacement to 3.6mm for 40% replacement. The hard concrete had the highest compressive strength value of 23.67 N/mm2 for plain concrete and 49.3 N/mm2 at 5% GCHA replacement level. All were at 56 days of curing, satisfying quality for heavy load bearing. Beam samples cured for 3, 14, 28 and 56 days were subjected to flexural tests until they developed cracks. The cracks were measured for lengths (CRL) and width (CRW) for different replacement levels and curing days with a crack measuring microscope. The results show that, at 14days curing, there is a trend in the crack values’ reduction for the hardened GCHA concrete. This trend is also marginally seen for the 28 day cured samples, particularly at up to 20% replacement levels. The decrease in crack values were up to 17.2% and 2091% for CRL and CRW respectively. However, there were no significant crack controls with samples of higher replacement levels and those cured for 3 and 56 days. GCHA concrete can therefore be used to for heavy load bearing structures and for crack control at 5 – 20% replacement levels when cured for 14 days and 38 days.

The Effect of Volumetric Hydrophobization on Moisture Transfer during Hardening of Concrete

The influence of volumetric hydrophobization of cement stone samples on mass transfer processes during hardening has been studied. It was found that the introduction of a hydrophobizing additive at the stage of sample production reduces the amount of water evaporating during drying. With increasing concentration of the hydrophobizer mass transfer processes are slowed down during the hardening of cement concretes, which affects their structural and phase composition, strength characteristics and durability.

Evaluation of compressive strength investigation on job mix test object and core drill test object

The test sample in the core drill is a hard concrete test (ASTM C-39) method by taking samples of concrete cylinders from areas of compressive strength is doubtful. Sampling is done by drill tool which drill is in the form of “pipe” from diamond, so that the concrete sample is obtained in the form of cylinder. Building made of concrete construction, it must be required corresponding the required strength through planning determined by testing the quality of concrete on the job mix SNI test standard, but in the process of concreting that does not be corresponding the method and the conditions that must be obeyed often results in strength the concrete construction that has been built does not achieve the desired strength. When the existing concrete building strength checks are carried out, it is necessary to evaluate how much the error or the difference in the results of the test on the concrete quality of the planning and quality of hard concrete that is ready to be built. For this reason, one of the hard concrete strength tests is done by using the core drill method.

Experimental Investigation on PCC for Workability within Partial Replacement of M-Sand by Ecosand

In whole nation, concrete production events are enchanting abode on vast scale. Natural sand (river sand) is unique of the main requirements of concrete and it is pretty demand and exclusive. Manufactured sand (M-sand) is a standby of river sand for concrete assembly which is produced from rigid granite pebble by devastating. Eco-sand is fine particles which is outgrowth from cement trade. Effective use of this waste material should be done for cost efficiency. The present study is about the compressive strength of concrete block with limited surrogating of M-sand by Eco-sand. The conventional river sand is replaced with M sand and partial amount of silica sand Replacement of M-sand by Eco-sand at various percentages 0%, 6%, 12% 18%, 24%&30% in PCC.It is verified that the finest spare percentage of M-sand by Eco-sand and the properties of fresh concrete and hard concrete in PCC with eco-sand. The comparison of economic advantages of m sand and eco sand. The main objective of this project is to reduce the air pollution and eco-friendly. The various proportions is carried out and tested.

KUAT TEKAN SELF COMPACTING CONCRETE MENGGUNAKAN GROUND GRANULATED BLAST FURNACE SLAG

Self Compacting Concrete (SCC) as one type of concrete that is mostly used in building construction has good workability and can be obtained by adding filler instead of cement. Ground Granulated Blast Furnace Slag (GGBFS) has a chemical composition similar to the content in cement. Therefore, the study of the use of GGBFS was used as a partial substitute for cement in the SCC to examine the influences and quality of GGBFS on fresh concrete and to obtain SCC with the best compressive strength. This research method uses an experimental method by making SCC concrete specimens with an initial fas of 0.4 according to ACI 211.4R-93. The specimens were worked using GGBFS levels of 0%, until 80%, and using 1,4% superplasticizer, and 2% accelerator by weight of cement. The use of GGBFS at SCC can increase the value of compressive strength of about 4,27%-25,64 compared to SCC without using GGBFS. The resulted are known that GGBFS can influence compression strength. Based on the testing of fresh and hard concrete, it concluded that the best quality of SCC used 20% of GGBFS.