scholarly journals Effect of Using Limestone Fines on the Chemical Shrinkage of Pastes and Mortars

2021 ◽  
Author(s):  
Jamal Khatib ◽  
Rawan Ramadan ◽  
Hassan Ghanem ◽  
Adel ElKordi
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Chemical Shrinkage ◽  
Total Period ◽  
Binder Ratio ◽  
Limestone Fines ◽  
Water To Binder Ratio

Abstract The main aim of this study is to examine the effect of incorporating limestone fines (LF) on chemical shrinkage of pastes and mortars. For this purpose, five paste and five mortar mixes were prepared with 0, 5, 10, 15 and 20% (by weight) LF as replacement of cement. The water to binder ratio (w/b) was 0.45 for all mixes. The sand to binder (s/b) ratio in the mortar mixes was 2. Testing included chemical shrinkage, compressive strength, density and ultrasonic-pulse velocity (UPV). Chemical shrinkage was tested each hour for the first 24 hrs, and thereafter each 2 days until a total period of 90 days. Furthermore, compressive strength and UPV tests were conducted at 1 day, 7, 28 and 90 days of curing. The results show that the long-term chemical shrinkage of pastes was found to increase with the increase in LF content up to 15%. Beyond this level of replacement, the chemical shrinkage started to decrease. However, the chemical shrinkage for mortars increased with the increase in LF content up to 10% LF and a decrease was observed beyond this level. It was also noticed that compressive strength for pastes and mortars attained the highest value for mixes containing 10 and 15% LF. The trend in the UPV results is somewhat similar to those of strength. Density for pastes and mortars increased up to 15% LF followed by a decrease at 20 % replacement level. Correlations between the various properties were conducted. It was found that an increase in chemical shrinkage led to an increase in compressive strength.

scholarly journals Utilization of Metakaolin and Calcite: Working Reversely in Workability Aspect—As Mineral Admixture in Self-Compacting Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fatih Özcan ◽  
Halil Kaymak
Keyword(s):  
Compressive Strength ◽  
High Strength ◽  
High Volume ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Mineral Admixture ◽  
Self Compacting Concrete ◽  
Binder Ratio

In this work, utilization of metakaolin (MK) and calcite (C), working reversely in workability aspect, as mineral admixture in self-compacting concrete (SCC), was investigated. MK and C replaced cement in mass basis at various replacement ratios, separately and together. In total, 19 different SCCs were produced. Binder content and water to binder ratio were selected as 500 kg/m3 and 0.4, respectively. Workability tests including slump flow, T50, L-box, and V-funnel tests were performed. Consistency and setting times of binder paste were measured. While replacement of MK with cement increased the amount of plasticiser requirement, calcite worked reversely and decreased it. Reverse influence of MK and C on plasticiser requirement of SCC made possible to produce SCC at total 45% replacement ratio of MK and C together. Samples of SCC were cured in water at 20°C temperature. Compressive strengths of SCC samples were measured up to six months to evaluate the influence of MK and C, separately and together. Ultrasonic pulse velocity, abrasion, and capillary water absorption values of samples were determined at specified age. MK inclusion in concrete reduces workability, while C inclusion increases it. C and MK inclusion together remedied workability of concrete and enabled to produce SCC with high volume of admixtures. Furthermore, C incorporation increased one-day compressive strength, while MK incorporation reduced it in comparison with control concrete. In long term, C inclusion reduced compressive strength; however, MK inclusion increased it. C inclusion remedied one-day strength of concrete when it was used together with MK. MK inclusion remedied long-term compressive strength when it was used together with C and enabled to produce high-strength SCC with high volume of admixtures. SCC containing MK and C together showed better durability-related property.

scholarly journals The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

2021 ◽  
Vol 13 (4) ◽  
pp. 1881
Author(s):  
Mei-Yu Xuan ◽  
Yi Han ◽  
Xiao-Yong Wang
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Experimental Studies ◽  
Autogenous Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Hydration Heat ◽  
Granulated Blast Furnace Slag ◽  
Binder Ratio

This study examines the hydration–mechanical–autogenous shrinkage–durability–sustainability properties of ternary composites with limestone filler (LF) and ground-granulated blast furnace slag (BFS). Four mixtures were prepared with a water/binder ratio of 0.3 and different replacement ratios varying from 0 to 45%. Multiple experimental studies were performed at various ages. The experimental results are summarized as follows: (1) As the replacement levels increased, compressive strength and autogenous shrinkage (AS) decreased, and this relationship was linear. (2) As the replacement levels increased, cumulative hydration heat decreased. At the age of 3 and 7 days, there was a linear relationship between compressive strength and cumulative hydration heat. (3) Out of all mixtures, the ultrasonic pulse velocity (UPV) and electrical resistivity exhibited a rapid increase in the early stages and tended to slow down in the latter stages. There was a crossover of UPV among various specimens. In the later stages, the electrical resistivity of ternary composite specimens was higher than plain specimens. (4) X-ray diffraction (XRD) results showed that LF and BFS have a synergistic effect. (5) With increasing replacement ratios, the CO2 emissions per unit strength reduced, indicating the sustainability of ternary composites.

scholarly journals Volume Stability of Cement Paste Containing Limestone Fines

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 366
Author(s):  
Jamal Khatib ◽  
Rawan Ramadan ◽  
Hassan Ghanem ◽  
Adel Elkordi
Keyword(s):  
Cement Paste ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Total Period ◽  
Volume Stability ◽  
Cement Replacement ◽  
Binder Ratio ◽  
Limestone Fines ◽  
Water To Binder Ratio

The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss of water and chemical reactions. Incorporating limestone fines (LF) as a cement replacement can affect the shrinkage of the paste. To examine this effect, five paste mixes were prepared with 0, 5, 10, 15 and 20% LF as a cement replacement and with a water-to-binder ratio (w/b) of 0.45. Four volume stability tests were conducted for each paste: chemical, autogenous and drying shrinkage and expansion. Chemical shrinkage was tested each hour for the first 24 h and thereafter every 2 days for a total period of 90 days. The drying shrinkage, autogenous shrinkage and expansion were monitored every 2 days until 90 days. The results showed that replacing 15% LF enhanced the chemical shrinkage of the paste. However, autogenous shrinkage of the paste was found to increase between 0 and 10% LF and decline sharply at 15 and 20% LF. Drying shrinkage was found to increase with the increase in LF content. Expansion exhibited little variation between 0 and 10% LF and an increase for replacement above 15% LF. These results are discussed in terms of the formation of hydration products and self-desiccation due to hydration.

PENGKAJIAN KEKUATAN BETON STRUKTUR JEMBATAN PASCA KEBAKARAN

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Strength Assessment ◽  
Concrete Testing

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.

scholarly journals Mechanical Characterisation and Shrinkage of Thermoactivated Recycled Cement Concrete

2021 ◽  
Vol 11 (6) ◽  
pp. 2454
Author(s):  
Sofia Real ◽  
José Alexandre Bogas ◽  
Ana Carriço ◽  
Susana Hu
Keyword(s):  
Mechanical Strength ◽  
Elasticity Modulus ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Concrete ◽  
Supplementary Cementitious Material ◽  
Mechanical Characterisation ◽  
Shrinkage Behaviour ◽  
Binder Ratio

This paper investigates the mechanical and shrinkage behaviour of concrete with recycled cement (RC) thermoactivated from waste cement paste and waste concrete. Overall, compared to ordinary Portland cement (OPC), for the same water/binder ratio, the mechanical strength and ultrasonic pulse velocity were not significantly influenced by the incorporation of RC. The elasticity modulus decreased with the addition of RC and the shrinkage tended to increase at high RC content. The incorporation of up to 15% RC allowed the production of workable concrete with identical shrinkage and similar to higher mechanical strength than concrete with only OPC. RC proved to be a very promising more eco-efficient supplementary cementitious material.

Estimation of Compressive Strength of Recycled Aggregate High Strength Concrete Using Ultrasonic Pulse Velocity

2014 ◽  
Vol 605 ◽  
pp. 147-150
Author(s):  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
Yong Taeg Lee
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Coarse Aggregate ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Recycled Aggregate ◽  
Strength Concrete ◽  
Recycled Coarse Aggregate

This study used the ultrasonic pulse velocity method, one of the non-destructive test methods that does not damage the building for maintenance of to-be-constructed concrete structures using recycled aggregates in order to estimate the compressive strength of high strength concrete structure using recycled coarse aggregate and provide elementary resources for technological establishment of ultrasonic pulse velocity method. 200 test pieces of high strength concrete 40, 50MPa using recycled coarse aggregate were manufactured by replacement rates (0, 30, 50, 100%) and age (1, 7, 28, 180days), and air curing was executed to measure compressive strength and wave velocity. As the result of compressive strength measurement, the one with age of 180day and design strength of 40MPa was 43.69MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 42.82, 41.22, 37.35MPa, and 50MPa was 52.50MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 49.02, 46.66, 45.30MPa, and while it could be seen that the test piece substituted with recycled aggregate was found to have lower strength than the test piece with natural aggregate only, but it still reached the design strength to a degree. The correlation of compressive strength and ultrasonic pulse velocity was found and regression analysis was conducted. The estimation formula for compressive strength of high strength concrete using recycled coarse aggregate was found to be Fc=0.069Vp4.05, R2=0.66

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