scholarly journals Modelling the minislump spread of superplasticized PPC paste using Random forest, Decision tree and Multiple linear regression

2021 ◽  
Vol 2070 (1) ◽  
pp. 012126
Author(s):  
M Mrithula ◽  
Modepu Bhavana ◽  
S Janani ◽  
Vaishnavi Narayanan ◽  
C.B Rajesh ◽  
...  
Keyword(s):  
Random Forest ◽  
Decision Tree ◽  
Cement Paste ◽  
Flow Rate ◽  
Flow Speed ◽  
Training Data ◽  
Cement Particle ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Family

Abstract Workability is one of the key property of concrete which is governed by water cement ratio. In order to improve the workability of concrete without any variations in water cement ratio Superplasticizers(SPs) are added. Cement paste helps us to analyze the property of fresh concrete where the dispersion of cement particle is taken into account. SP’s Cement dispersive properties are governed by dosage and the family. Various dosages and families of SP are considered for estimating workability feature of cement paste which is picked for investigating on rheological properties through Mini slump spread diameter. The prime motive of this analysis includes measuring the workability of different superplasticizers by conducting a minislump test and hence modelling the flow rate of the superplasticized Portland Pozzolona Cement (PPC)paste using the application of random forest(RF), decision tree(DT) and multiple regression algorithms. Testing and training data for a model were 287 unique mixture compositions at a water by cement ratio was 0.37. This mixture was tested experimentally in a laboratory using four types of locally available PPC’s and of SP which can be broadly categorised in to four families. Amount of seven types of SP brands, water content, cement weight were the input parameters for the model and flow rate was the output parameter. The model’s predicted and experimentally measured values of flow speed were compared and the amount of deviation was recorded.

scholarly journals Effect of water/cement ratio on micro-nanomechanical properties of the interface between cementitious matrix and steel microfibers in ultra-high performance cementitious composites

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Vanessa Fernandes Cesari ◽  
Fernando Pelisser ◽  
Philippe Jean Paul Gleize ◽  
Milton Domingos Michel
Keyword(s):  
Transition Zone ◽  
Cement Paste ◽  
Calcium Silicate ◽  
High Performance ◽  
Calcium Silicate Hydrate ◽  
Interfacial Transition Zone ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Nanomechanical Properties ◽  
Cementitious Matrix

abstract: Ultra-high performance concretes with steel microfibers have been studied in depth with the aim of producing more efficient and durable structures. The performance of these materials depends on the characteristics of the interface between microfibers and cementitious matrix. This research investigates the micro-nanomechanical properties of the interfacial transition zone between the steel microfibers and the matrix of ultra-high performance cementitious composite. The effect of the water/cement ratio and distance from the microfiber were analyzed. The results confirm the formation of high-density calcium-silicate-hydrate (HD C-S-H) matrix at higher concentrations than low-density calcium-silicate-hydrate (LD C-S-H) for w/c ratios of 0.2 and 0.3. The properties in cementitious matrix interface with steel microfibers were very similar to that measured for the cement paste, and no significant difference was observed regarding the distance to the microfibers in relation to the elastic modulus, hardness and chemical composition. Thus, the authors can conclude that the formation of a less resistant region does not occur at the interfacial transition zone cement paste/microfibers.

Microstructure of High Strength Cement Paste Systems

1984 ◽  
Vol 42 ◽  
Author(s):  
M. Regourd
Keyword(s):  
Cement Paste ◽  
Ultrafine Particles ◽  
High Strength ◽  
Interfacial Bond ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Composite Systems ◽  
Crystalline Hydrates ◽  
Low Porosity

AbstractHigh strength cement pastes include hot pressed, autoclaved, impregnated low water/cement ratio, macrodefect free, ultrafine particles arrangement systems. The densification of the microstrucure is mainly related to a low porosity and to the formation of poorly crystalline hydrates. In composite systems like mortars and concretes, the interfacial bond between the cement paste and aggregates is moreover less porous and more finely crystallized than the normal “auréole de transition”.

Evaluation of initial setting time due to superplasticizers

2017 ◽  
Vol 8 (2) ◽  
pp. 65
Author(s):  
Abhishek Singh ◽  
Shobha Ram ◽  
Alok Verma
Keyword(s):  
Water Content ◽  
Cement Paste ◽  
Setting Time ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Initial Setting Time ◽  
Initial Setting

This paper shows how polycarboxylate based superplasticizer affects the initial setting time of cement paste. Three superplasticizers are used in this study with different properties and aiming to determine the delay in initial setting time due to superplasticizer. Initial setting time is calculated as per IS: 4031-PART 5-1988 with different SP dosages (0.5%, 0.75%, 1.0% and 1.5% of weight of cement). Superplasticizer is an admixture which reduces the water-cement ratio or increase the workability at the same water content. This paper deals with the evaluation of initial setting time due to superplasticizers.

scholarly journals Strength and Deformability of Fiber Reinforced Cement Paste on the Basis of Basalt Fiber

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Yury Barabanshchikov ◽  
Ilya Gutskalov
Keyword(s):  
Crack Resistance ◽  
Cement Paste ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Fiber Reinforced ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Particulate Reinforcement ◽  
Reinforced Cement ◽  
Basaltic Fiber

The research object of the paper is cement paste with the particulate reinforcement of basalt fiber. Regardless of fibers’ length at the same fiber cement mix workability and cement consumption equality compressive solidity of the specimens is reduced with increasing fiber content. This is due to the necessity to increase the water-cement ratio to obtain a given workability. The flexural stability of the specimens with increasing fiber content increments in the same conditions. There is an optimum value of the fibers’ dosage. That is why stability has a maximum when crooking. The basaltic fiber particulate reinforcement usage can abruptly increase the cement paste level limiting extensibility, which is extremely important in terms of crack resistance.

Prediction of Elastic Modulus of Cement-Based Materials Based on Power’s Volume Model

2012 ◽  
Vol 253-255 ◽  
pp. 474-477 ◽  
Author(s):  
Lang Wu ◽  
Bing Yan ◽  
Bin Lei
Keyword(s):  
Elastic Modulus ◽  
Elastic Properties ◽  
Cement Paste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Micromechanics Model ◽  
Volume Model ◽  
Cement Based Materials ◽  
Hydrated Products ◽  
Multi Phase

The hydrated products, unhydrated cement and water (capillary pores) in the cement paste are seen as matrix, inclusion, Equivalent medium respectively, We used the micromechanics theories and Power’s Volume model to develop a multi-phase micromechanics model capable of simulating the elastic properties of cement-based materials, and the evolution of elastic properties in the hydration process was calculated at different water-cement ratio. The final experimental results show that this model can be used to predict the elastic properties of cement-based materials.

scholarly journals The Assessment of Strength of Cementitious Materials Impregnated Using Hydrophobic Agents Based on Near-Surface Hardness Measurements

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4583
Author(s):  
Martyna Nieświec ◽  
Łukasz Sadowski
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Concrete Structures ◽  
Surface Hardness ◽  
Cementitious Materials ◽  
Schmidt Hammer ◽  
Near Surface ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Impact

Recently, the surfaces of concrete structures are impregnated to protect them against the environment in order to increase their durability. It is still not known how the use of these agents affects the near-surface hardness of concrete. This is especially important for experts who use the near-surface hardness of concrete for estimating its compressive strength. The impregnation agents are colorless and, thus, without knowledge of their use, mistakes can be made when testing the surface hardness of concrete. This paper presents the results of investigations concerning the impact of impregnation on the subsurface hardness concrete measured using a Schmidt hammer. For this research, samples of cement paste with a water–cement ratio of 0.4 and 0.5 were used. The samples were impregnated with one, two, and three layers of two different agents. The first agent has been made based on silanes and siloxanes and the second agent has been made based on based on polymers. The obtained research results allow for the conclusion that impregnation affects the near-surface hardness of concrete. This research highlights the fact that a lack of knowledge about the applied impregnation of concrete when testing its near-surface hardness, which is then translated into its compressive strength, can lead to serious mistakes.

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