scholarly journals Evaluating Prediction Models of Creep and Drying Shrinkage of Self-Consolidating Concrete Containing Supplementary Cementitious Materials/Fillers

2021 ◽  
Vol 11 (16) ◽  
pp. 7345
Author(s):  
Micheal Asaad ◽  
George Morcous
Keyword(s):  
Prediction Models ◽  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Self Consolidating Concrete ◽  
Powder Filler ◽  
Paste Content ◽  
Predicted Values ◽  
Aashto Lrfd

Supplementary cementitious materials (SCMs) and fillers play an important role in enhancing the mechanical properties and durability of concrete. SCMs and fillers are commonly used in self-consolidating concrete (SCC) mixtures to also enhance their rheological properties. However, these additives could have significant effects on the viscoelastic properties of concrete. Existing models for predicting creep and drying shrinkage of concrete do not consider the effect of SCM/filler on the predicted values. This study evaluates existing creep and drying shrinkage models, including AASHTO LRFD, ACI209, CEB-FIP MC90-99, B3, and GL2000, for SCC mixtures with different SCMs/fillers. Forty SCC mixtures were proportioned for different cast-in-place bridge components and tested for drying shrinkage. A set of eight SCC mixtures with the highest paste content was tested for creep. Shrinkage and creep test results indicated that AASHTO LRFD provides better creep prediction than the other models for SCC with different SCMs/fillers. Although all models underestimate drying shrinkage of SCC with different SCMs/fillers, the GL2000, CEB-FIP MC90-99, and ACI 209 models provide better prediction than AASHTO LRFD and B3 models. Additionally, SCC mixtures with limestone powder filler exhibited the highest creep, while those with class C fly ash exhibited the highest drying shrinkage.

Use of Fiber-Reinforced Self-Consolidating Concrete to Enhance Serviceability Performance of Damaged Beams

2018 ◽  
Vol 2672 (27) ◽  
pp. 45-55 ◽  
Author(s):  
Haider A. Abdulhameed ◽  
Hani Nassif ◽  
Kamal H. Khayat
Keyword(s):  
Polypropylene Fiber ◽  
Cementitious Materials ◽  
Load Level ◽  
Supplementary Cementitious Materials ◽  
Flexural Behavior ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Reinforcing Bars ◽  
Self Consolidating Concrete ◽  
Predicted Values

The use of fiber-reinforced self-consolidating concrete (FR-SCC) in repairing damaged concrete beams has been evaluated. An experimental program was conducted to design and test key fresh and hardened properties of SCC and FR-SCC mixtures. The designed FR-SCC mixtures included two types of supplementary cementitious materials (silica fume (SF) and slag (SL)) and two types of fibers (steel fiber (STF) and polypropylene fiber (PPF)) were used. To ensure good workability to repair congested areas, the optimized volume fractions of the STF were 0.25% and 0.50% compared with 0.10%, 0.15%, and 0.20% for the PPF. In addition, the flexural behavior of 10 beam specimens was investigated. The main reinforcement for the control beams consisted of #5 reinforcing bars, while the main reinforcement for the repaired beams was either #4 or #3 reinforcing bars that were introduced to simulate 35% and 65% reduction of the bar areas, respectively, due to corrosion. The results demonstrate that the optimized FR-SCC mixtures are effective repair materials and can develop adequate bond strength to existing concrete. The flexural test results showed that the repair mixtures were able to increase the cracking load for the repaired beams compared with the control beams. Such an increase is expected to contribute to extending the life of the damaged member or structure at the service load level. This paper also presents a comparison of the predicted values for the first-crack load strength using the ACI 544 code equation with the experimental data. Results showed that the code equation provides safe prediction.

Performance of Impure Calcined Clay as a Pozzolan in Concrete

2020 ◽  
pp. 036119812095314
Author(s):  
Khashayar Jafari ◽  
Farshad Rajabipour
Keyword(s):  
Portland Cement ◽  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Strength Development ◽  
Natural Pozzolan ◽  
Quartz Content ◽  
Calcined Clay ◽  
Air Content ◽  
Sand And Gravel

Supplementary cementitious materials (SCMs) are natural or industrial by-product materials which are used to improve the performance, durability, and sustainability of concrete mixtures. Motivated by the recent reports on shortage of conventional SCMs, impure calcined clays (CCs) are receiving attention as abundant alternative pozzolans for concrete. In this study, a clay slurry resulting from washing aggregates in a commercial sand and gravel pit was investigated. This source clay was dried and calcined, and the properties and pozzolanic performance of the resulting CC was evaluated. It was observed that despite having a large (>50%wt.) inert quartz content, the CC met all ASTM C618-19 (AASHTO M295) requirements for natural pozzolan. A pavement-grade concrete mixture containing 20%CC as a cement replacement (by weight) produced desired workability and fresh and hardened air content. Strength development was slightly below the control. The use of CC improved the durability of concrete with respect to chloride penetration, alkali–silica reaction, and drying shrinkage in comparison with a control (100% Portland cement) mixture. In addition, ternary limestone-calcined clay–cement and slag-calcined clay–cement mortar mixtures showed excellent strength development while replacing nearly 50% of the Portland cement.

scholarly journals Study of Hydration and Microstructure of Mortar Containing Coral Sand Powder Blended with SCMs

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4248
Author(s):  
Xingxing Li ◽  
Ying Ma ◽  
Xiaodong Shen ◽  
Ya Zhong ◽  
Yuwei Li
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Silica Fume ◽  
Dilution Effect ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Chemical Effect ◽  
Granulated Blast Furnace Slag ◽  
Coral Sand

The utilization of coral waste is an economical way of using concrete in coastal and offshore constructions. Coral waste with more than 96% CaCO3 can be ground to fines and combined with supplementary cementitious materials (SCMs) such as fly ash, silica fume, granulated blast furnace slag in replacing Portland cement to promote the properties of cement concrete. The effects of coral sand powder (CSP) compared to limestone powder (LSP) blended with SCMs on hydration and microstructure of mortar were investigated. The result shows CSP has higher activity than LSP when participating in the chemical reaction. The chemical effect among CSP, SCMs, and ordinary Portland cement (OPC) results in the appearance of the third hydration peak, facilitating the production of carboaluminate. CSP-SCMs mortar has smaller interconnected pores on account of the porous character of CSP as well as the filler and chemical effect. The dilution effect of CSP leads to the reduction of compressive strength of OPC-CSP and OPC-CSP-SCMs mortars. The synergic effects of CSP with slag and silica fume facilitate the development of compressive strength and lead to a compacted isolation and transfer zone (ITZ) in mortar.

Effect of Aggregate Max Size on the Rheological Properties of Self Consolidating Concrete

2020 ◽  
Vol 853 ◽  
pp. 193-197
Author(s):  
Samer Al Martini ◽  
Ziad Hassan ◽  
Ahmad Khartabil
Keyword(s):  
Blast Furnace Slag ◽  
Aggregate Size ◽  
Maximum Size ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Self Consolidating Concrete ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mixtures ◽  
Time Period ◽  
Furnace Slag

The effects of aggregate size and supplementary cementitious materials (SCMs) on the rheology of self-consolidating concrete (SCC) were studied in this paper. Two main concrete mixtures with different maximum aggregate sizes were prepared and investigated. The first mix had a maximum size aggregate of 5 mm and the second mix was with 20 mm max size aggregates. All mixes incorporated different dosages of Ground granulated blast furnace slag (GGBS). The rheology of all mixes investigated was measured over 2 hour time period. It was found that the size of aggregates and GGBS dosage have influence on the yield stress of studied concrete mixes.

scholarly journals Synthesis of a New Polycarboxylate at Room Temperature and Its Influence on the Properties of Cement Pastes with Different Supplementary Cementitious Materials

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Shuncheng Xiang ◽  
Yingli Gao ◽  
Caijun Shi
Keyword(s):  
Room Temperature ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Heat Evolution ◽  
Hydration Heat ◽  
Supplementary Cementitious Materials ◽  
Cement Pastes ◽  
Binder Ratio ◽  
Water Binder Ratio

Three polycarboxylates with different comb structures (i.e., the same degree of polymerization in side chains but different main chains) were synthesized via radical polymerization reaction at room temperature. The effect of polycarboxylates on the surface tension and the flowability in cement pastes was determined. The best product was selected to study its effects on the hydration heat evolution, compressive strength, autogenous shrinkage, and drying shrinkage of cement pastes with different kinds and contents of supplementary cementitious materials. The results showed that with the increase of molar ratio between AA and TPEG to 6 : 1, we could synthesis the best product. When the water-binder ratio was 0.4, with the increase of polycarboxylates, the cement hydration heat evolution had been slowed down, and the more the dosage was, the more obvious the effect was. Adding supplementary cementitious materials to cement under the same experimental conditions also played a mitigation role in slowing down the hydration heat. When the water-binder ratio was 0.3, supplementary cementitious materials could increase the strength of cement by 24.5% in maximum; its autogenous shrinkage and drying shrinkage could be decreased, respectively, by 60.1% and 21.9% in the lowest.

EFFECT OF ACCELERATED CURING ON ABRASION OF HIGH VOLUME SUPPLEMENTARY CEMENTITIOUS MATERIAL SELF CONSOLIDATING CONCRETE

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Hayder H. Alghazali ◽  
John J. Myers
Keyword(s):  
Prestressed Concrete ◽  
Abrasion Resistance ◽  
High Volume ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Supplementary Cementitious Materials ◽  
Supplementary Cementitious Material ◽  
Self Consolidating Concrete ◽  
Accelerated Curing ◽  
Precast Prestressed Concrete

Sustainability of precast/prestressed concrete plant can be promoted by using supplementary cementitious material and that significantly reduces the embodied energy of precast/ prestressed concrete products. Usually, up to 25% of the cement can be replaced with supplementary cementitious materials (SCM). Increasing the level of replacement to exceed 25% is considered to be High-Volume SCM. Appropriate testing should be conducted to ensure desired performance of the concrete. This context reports the results of an experimental investigation of effect of accelerated curing on abrasion resistance of High Volume Supplementary Cementitious Material – Self Consolidating Concrete (HVSCM-SCC). Different mixes proportion with supplementary cementitious materials such as Fly Ash, Micro Silica, and lime (Up to 75% of cement replacement) were tested. Rheological properties of the HVSCM-SCC were measured. Mechanical properties at different ages 1, 3, 7, 28, 56, and 90 days were monitored. To investigate the abrasion resistance, 12 x 12 x 3.5 in specimens at age of 28, 56, and 90 days were conducted. The results of abrasion resistance of HVSCM-SCC were compared to the same mixes cured in the moist room. The result showed that the accelerated curing has a significant influence on abrasion resistance of concrete at early ages.

Flow Behavior of Self Consolidating Concrete Mixes with Various Maximum Size Aggregates

2019 ◽  
Vol 803 ◽  
pp. 233-238 ◽  
Author(s):  
Samer Al Martini ◽  
Ziad Hassan ◽  
Ahmad Khartabil
Keyword(s):  
Fly Ash ◽  
Flow Behavior ◽  
Aggregate Size ◽  
Maximum Size ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Binary Blends ◽  
Self Consolidating Concrete ◽  
Slump Flow

The paper investigates the effects of aggregate size and supplementary cementitious materials (SCMs) on flow behavior of self-consolidating concrete (SCC). The fresh performance of concrete mixes was evaluated through slump flow and V funnel tests. Some concrete mixes were prepared with 5 mm maximum size aggregates and other mixes with 20 mm maximum size aggregates. The effects of varying contents of SCMs (Fly ash F and GGBS) on flow behavior of SCC under binary blends were also studied. The results show that the maximum size of aggregates has effect on the flow behavior of SCC.

scholarly journals Hydration–Strength–Workability–Durability of Binary, Ternary, and Quaternary Composite Pastes

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 204
Author(s):  
Yi Han ◽  
Seokhoon Oh ◽  
Xiao-Yong Wang ◽  
Run-Sheng Lin
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Carbon Emissions ◽  
Cementitious Materials ◽  
Heat Of Hydration ◽  
Surface Resistivity ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Alternative Materials

At present, reducing carbon emissions is an urgent problem that needs to be solved in the cement industry. This study used three mineral admixtures materials: limestone powder (0–10%), metakaolin (0–15%), and fly ash (0–30%). Binary, ternary, and quaternary pastes were prepared, and the specimens’ workability, compressive strength, ultrasonic pulse speed, surface resistivity, and the heat of hydration were studied; X-ray diffraction and attenuated total reflection Fourier transform infrared tests were conducted. In addition, the influence of supplementary cementitious materials on the compressive strength and durability of the blended paste and the sustainable development of the quaternary-blended paste was analyzed. The experimental results are summarized as follows: (1) metakaolin can reduce the workability of cement paste; (2) the addition of alternative materials can promote cement hydration and help improve long-term compressive strength; (3) surface resistivity tests show that adding alternative materials can increase the value of surface resistivity; (4) the quaternary-blended paste can greatly reduce the accumulated heat of hydration; (5) increasing the amount of supplementary cementitious materials can effectively reduce carbon emissions compared with pure cement paste. In summary, the quaternary-blended paste has great advantages in terms of durability and sustainability and has good development prospects.

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