High Efficiency Ecological Concrete

2014 ◽  
Vol 604 ◽  
pp. 157-160 ◽  
Author(s):  
Patricija Kara ◽  
Aleksandrs Korjakins
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Portland Cement ◽  
Alkaline Earth ◽  
High Efficiency ◽  
Cement Content ◽  
Soda Lime ◽  
Waste Glass ◽  
Concrete Mixture ◽  
Concrete Properties

Waste glass is cementitious in nature when it is finely ground, and especially when it is ground in a wet environment it can be finer than Portland cement. The obtained borosilicate lamp waste glass slurry with a grain size of 0.713 – 8.088 μm has shown better fineness and stability to segregation in comparison to soda-lime and soda-alkaline earth-silicate waste glasses. Elaborated high efficiency concrete with borosilicate lamp waste glass showed 120 MPa compressive strength at 28 days and it can be considered as ecological due to reduced cement content for 20% in concrete mixture without changing concrete properties in a negative way, reduced CO2 and waste glass deposits.

scholarly journals Experimental Study on Mechanical Properties and Structural Characteristics of Modified Sludge in Foundation Pit

CONVERTER ◽  
2021 ◽  
pp. 11-21
Author(s):  
Shuren Wang, Et al.
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
High Efficiency ◽  
Cement Content ◽  
Structural Characteristics ◽  
Curing Time ◽  
Hydration Products ◽  
Foundation Pit ◽  
Early Strength

To explore the efficient method of sludge modification, Ultra-fine Portland cement (UPC) was introduced as a sludge modifier regarding Ordinary Portland Cement (OPC) modified sludge as a reference. The mechanical properties and microstructural changes of UPC-modified sludge with different curing time and cement content were carried out by unconfined compressive strength (UCS), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) tests. Results show that the UCS of UPC-modified sludge varies with curing time and cement content in the same way as that of OPC-modified sludge. However, compared with OPC-modified sludge, UPC has a higher sludge modification efficiency, and the UPC-modified sludge has greater compressive strength, significantly early-strength, and stronger resistance to deformation. The stress-strain curves of UPC-modified sludge present significant peak stresses, and which show a brittle failure mode. The combination of the hydration products calcium silicate hydrate (C-S-H) gels and ettringite (Aft) crystals are the essential reason for the improvement of the macroscopic strength of the modified sludge. In contrast to OPC, the UPC hydrates faster and more fully. The UPC-modified sludge can generate more hydration products under the same conditions, this is why that has high efficiency and early-strength. The conclusions obtained in this study can provide a reference for the similar engineering application of ultra-fine cement in modified sludge.

scholarly journals Artificial Neural Network Estimation of the Effect of Varying Curing Conditions and Cement Type on Hardened Concrete Properties

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Gökhan Kaplan ◽  
Hasbi Yaprak ◽  
Selçuk Memiş ◽  
Abdoslam Alnkaa
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Limestone Powder ◽  
Mineral Admixtures ◽  
Hardened Concrete ◽  
Slag Cement ◽  
Curing Conditions ◽  
Concrete Properties ◽  
Concrete Production ◽  
Artificial Neural

The use of mineral admixtures and industrial waste as a replacement for Portland cement is recognized widely for its energy efficiency along with reduced CO2 emissions. The use of materials such as fly ash, blast-furnace slag or limestone powder in concrete production makes this process a sustainable one. This study explored a number of hardened concrete properties, such as compressive strength, ultrasonic pulse velocity, dynamic elasticity modulus, water absorption and depth of penetration under varying curing conditions having produced concrete samples using Portland cement (PC), slag cement (SC) and limestone cement (LC). The samples were produced at 0.63 and 0.70 w/c (water/cement) ratios. Hardened concrete samples were then cured under three conditions, namely standard (W), open air (A) and sealed plastic bag (B). Although it was found that the early-age strength of slag cement was lower, it was improved significantly on 90th day. In terms of the effect of curing conditions on compressive strength, cure W offered the highest compressive strength, as expected, while cure A offered slightly lower compressive strength levels. An increase in the w/c ratio was found to have a negative impact on pozzolanic reactions, which resulted in poor hardened concrete properties. Furthermore, carbonation effect was found to have positive effects on some of the concrete properties, and it was observed to have improved the depth of water penetration. Moreover, it was possible to estimate the compressive strength with high precision using artificial neural networks (ANN). The values of the slopes of the regression lines for training, validating and testing datasets were 0.9881, 0.9885 and 0.9776, respectively. This indicates the high accuracy of the developed model as well as a good correlation between the predicted compressive strength values and the experimental (measured) ones.

scholarly journals The Effect of Clay Pozzolana-Cement-Composite on the Strength Development of a Hydraulic Backfill

2018 ◽  
Vol 18 (1) ◽  
pp. 32-38
Author(s):  
S. N. Eshun ◽  
Solomon Senyo Robert Gidigasu ◽  
S. K. Y. Gawu
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Unconfined Compressive Strength ◽  
Ordinary Portland Cement ◽  
Cement Content ◽  
Cylindrical Specimen ◽  
Cement Composite ◽  
Strength Development ◽  
Increased Risk ◽  
Economic Considerations

The study sought to investigate the potential application of clay pozzolana as a supplement for cement in hydraulic backfill, using classified tailings from AngloGold Ashanti, Obuasi Mine. The percentage of the Portland cement that could be substituted with the clay pozzolana to produce backfill with best strength was determined. 10%, 25%, 30%, 35% and 40% of the ordinary Portland cement were replaced with clay pozzolana and then mixed with tailings and water. The slurry produced was cast into cylindrical specimen of 50mm diameter by 120mm high and tested for compressive strength after curing for 7, 14, 21, 28 and 56 days. The results indicate that, clay pozzolana-cement composite has potential for application in hydraulic back fill production without increased risk to safety and dilution. It was noted that hydraulic backfill with 10%, 25%, 30% and 35% of the ordinary portland cement replaced with clay pozzolana had strengths greater than those obtained for ordinary portland cement alone. Ten percent (10%) pozzolana content gave the maximum strength followed by 25% pozzolana. It is recommended that for safety and economic considerations, the cement content should be replaced by 25% pozzolana in the production of backfills. Keywords: Hydraulic Backfill, Portland Cement, Clay Pozzolana, Unconfined Compressive Strength

scholarly journals Performance of concrete with the incorporation of waste from the process of stoning and polishing of glass as partial replacement of cement

2020 ◽  
Vol 13 (3) ◽  
pp. 613-627
Author(s):  
G. C. GUIGNONE ◽  
G. L. VIEIRA ◽  
R. ZULCÃO ◽  
M. K. DEGEN ◽  
S. H. M. MITTRI ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flat Glass ◽  
Soda Lime ◽  
Waste Glass ◽  
Partial Replacement ◽  
Chloride Permeability ◽  
Alkali Silica Reactivity ◽  
And Migration ◽  
Strength And Durability ◽  
Cementing Material

Abstract The incorporation of waste glass as a partial replacement for cement in concrete can provide an alternative destination for the waste, reduce the consumption of cement (minimizing CO2 emissions and consumption of natural resources), and improve the concrete performance. Thus, this research evaluated the performance of concrete incorporating waste glass sludge (GS), resulting from the process of stoning and polishing of soda-lime flat glass, as a supplementary cementing material. Mechanical strength and durability properties were assessed through compressive strength, alkali-silica reactivity, electrical resistivity and chloride permeability, diffusivity and migration tests. Mixtures containing metakaolin (ME) were also evaluated. The results indicated that the use of the waste ground to an adequate size can replace up to 20% of cement. At this content, it caused a reduction of chloride penetration of over 80%, reduced ASR and conserved compressive strength. The combination of waste with metakaolin replacing 20% of cement also improved all the concrete properties, increasing the compressive strength up to 12% at 28 days.

scholarly journals Strength development of cement-treated sand using different cement types cured at different temperatures

2018 ◽  
Vol 195 ◽  
pp. 01006
Author(s):  
Lanh Si Ho ◽  
Kenichiro Nakarai ◽  
Kenta Eguchi ◽  
Takashi Sasaki ◽  
Minoru Morioka
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Content ◽  
Bound Water ◽  
Pozzolanic Reaction ◽  
Strength Development ◽  
Different Temperatures ◽  
Early Strength

This study aimed to investigate the strength development of cement-treated sand using different cement types: ordinary Portland cement (OPC), high early strength Portland cement (HPC), and moderate heat Portland cement (MPC) cured at different temperatures. The cementtreated sand specimens were prepared with 8% of cement content and cured under sealed conditions at 20οC and 40οC, and mortar specimens were also prepared for reference. The results showed that the compressive strength of cement-treated sand increased in order of MPC, OPC, and HPC under high curing temperatures. It was interesting that the compressive strength of the specimens using HPC was much larger than that of the specimen using OPC and MPC under 20οC due to the larger amount of chemically bound water. Additionally, it was revealed that under high curing temperatures, the pozzolanic reaction was accelerated in the cement-treated sand; this may be caused by the high proportions of sand in the mixtures.

Evaluation of Fly Ash on the Basis of Mass Equivalent, Maturity Equivalent and Permeance

1985 ◽  
Vol 65 ◽  
Author(s):  
R. H. Mills
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Gas Flow ◽  
Concrete Mixture ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Efficiency Factors ◽  
Gas Tightness

ABSTRACTCombinations of two types of commercially available Fly Ash (FA) and Portland cement (PC) were tested for compressive strength and permeance to gas flow. The cementitious components were combined in the concrete mixture in proportions PC/FA = 100/0, 75/25, 60/40 and 45/55 for a range of water/cement ratio, and equal workability. Strength and maturity efficiency factors were satisfactory for 75/25 and 60/40 blends. Gas tightness was improved at all levels of Fly Ash substitution.

scholarly journals Assessing the Influence of Aggregates and Cement Types on Fresh Roller Compacted Concrete Mixture

2021 ◽  
pp. 23-31
Author(s):  
Saad I Sarsam
Keyword(s):  
Moisture Content ◽  
Portland Cement ◽  
Cement Content ◽  
Design Procedure ◽  
Concrete Mixture ◽  
Dry Density ◽  
Maximum Dry Density ◽  
River Sand ◽  
Roller Compacted Concrete ◽  
Crushed Aggregate

Roller compacted concrete mixture RCC is considered as a sustainable pavement construction material, it is a heavy-duty concrete mixture with zero slump. An attempt has been made in the present investigation to design the fresh RCC mixture using two types of coarse aggregates (crushed and rounded), two types of fine aggregates (silica and river sand) and two types of cement (ordinary Portland and sulphate resistance). Concrete mixtures with dense gradation were prepared and compacted according to modified proctor design procedure. A moisture-density test was used to determine the maximum density and optimum moisture content and of RCC mixtures for each mix.  Five different percentages of cement (10-18) % are implemented and six different percentages of moisture (4 – 8) %) % are used to determine the dry density-moisture content relationships. It was observed that the maximum dry density of rounded aggregates mixture is higher than that of crushed aggregate mixture by (4.2, 8.3, 4.2, 4.2, and 5.1) % and (4.1, 1.4, 4.1, 2.0, and 2.7) % for (18, 16, 14, 12, and 10) % cement content respectively for mixtures constructed with silica and river sands respectively with ordinary Portland cement. However, the maximum dry density of rounded aggregate mixture is higher than that of crushed aggregate mixture by (3.5, 4, 7.1, 5.5, and 4.4) % and (2.7, 4.8, 2.3, 4.4, and 4.2) % for (18, 16, 14, 12, and 10) % cement content respectively for mixtures constructed with silica and river sands respectively with sulphate resistance cement. It was concluded that 12 % of Portland cement and (6 to 7) % of moisture are proper combination when silica or river sand were implemented, while (12 and 14) % of sulphate resistance cement and (6 to 7) % of moisture are proper combination when silica or river sand were implemented. abstract must be a precise and reflection of what is in your article.

scholarly journals Some Mechanical Properties of Cement Treated Base (CTB) Incorporating Waste Portland Cement Concrete Under Different Corresponding Conditions

2018 ◽  
Vol 7 (4.37) ◽  
pp. 138
Author(s):  
Asst. Prof. Dr. Khawla H. H. Shubber ◽  
Eng. Sajjad Hashim Mohamed
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Granular Materials ◽  
Compression Strength ◽  
Cement Content ◽  
Strength Increase ◽  
Test Results ◽  
Portland Cement Concrete ◽  
Cement Concrete

This research represents a trial of understanding and improving mechanical properties of base or subbase granular materials, used in pavement construction, stabilized with Portland cement known as cement treated base (CTB) in terms of density, optimum water content (O.W.C), and compression Strength of three curing ages (3, 7, 28) days under different situations. Different Portland cement percent of (0, 5, 7, 10, 12, and 15) % by weight were added to selected base course granular materials (type B according to local standard specification in Iraq). Results showed that the density of mixture increase with increasing added cement percent, while O.W.C takes its maximum value around 7% cement content, and compression strength increase with increasing cement content and curing age. Then effect of replacing 50% of natural granular materials by waste Portland cement concrete (WPCC) was investigated on the results of (0, 7& 15)% cement content on density, O.W.C and compression strength in the three curing ages. Results reveled although density of mixture cooperating WPCC for 0% cement content was higher, CTB of natural granular material were denser. On the other hand compressive strength decrease in case of using WPCC for all percent cement added and curing ages. Finally, effect of soaking in water on CTB with (7 &15)% cement compressive strength of three curing ages was studied, under three period of soaking (1 week, 2 weeks, &one month). Test results exposed that, CTB Compressive strength increase with increasing soaking period but still less than that of un-soaked and for all curing ages. For each test stage mathematics relationships with acceptable correlation were presented proofing test results tendency.  

scholarly journals Soil characterization for adobe mixtures containing Portland cement as stabilizer

2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Lucas Miranda Araújo Santos ◽  
José Anselmo da Silva Neto ◽  
Aline Figueirêdo Nóbrega de Azerêdo
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Distribution Curve ◽  
Cement Content ◽  
Clay Content ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Physical And Chemical ◽  
Method Analysis

ABSTRACT One of the most economical ways to build with soil is to use adobe technique. There are several types of soils and most of them are not suitable for using to construct buildings. Physical and chemical characteristics of the soils will influence on its performance to use for buildings. This work aims to characterize physically, chemically and mineralogically two soil samples and study the dosage of mixtures for adobe using Portland cement as stabilizer. It was studied three different Portland cement content (6%, 9% and 12%) in the soil. The results showed that compressive strength of up to 5 MPa at 28 days for both type of soils studied with 12% of Portland cement. In addition, a comparison between two methods used for the particle size analysis of the soils. It was observed that the results differed in each method analysis. Overall this work has shown that to use these soils for adobe bricks, 9% of Portland cement is enough to reach the minimum compressive strength required by standard. Furthermore, this research brings results about the determination of the clay content of the soil, indicating that the traditional method to determine the size distribution curve by sieving and sedimentation may not be the most suitable to check this clay content.

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