scholarly journals Influences of shrinkage reducing admixture on the mechanical properties, drying shrinkage, water absorption and porosity of Portland cement mortar

2021 ◽  
Vol 15 (3) ◽  
pp. 55-67
Author(s):  
Nguyen Van Chinh
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Drying Shrinkage ◽  
Effective Porosity ◽  
Minor Effect ◽  
Wide Range ◽  
Shrinkage Reducing Admixture ◽  
A Minor

Drying shrinkage is the main cause of early age cracking of concrete and mortar. A wide range of research has been conducted to reduce the drying shrinkage, including using fibres or chemical admixtures. This paper investigated the effect of shrinkage reducing admixture on the flexural strength, compressive strength, drying shrinkage, water absorption and porosity of mortar. The mix compositions were ordinary Portland cement (OPC) : sand : liquid = 1: 1: 0.38 in which liquid consisted of water and shrinkage reducing admixture (SRA). SRA was used at the proportions of 2%, 4%, and 7% by weight of cement. The test results show that SRA reduces the flexural and compressive strengths of mortar. The reduction in flexural strength and compressive strength at 28 days is 14% and 25%, respectively at 7% SRA dosage. In addition, SRA significantly reduces the drying shrinkage and water absorption of mortar. At 7% SRA dosage, the drying shrinkage at 53 days is reduced by 60% while the water absorption rate at 24 hours is reduced by 54%. However, SRA has a minor effect on the pore size distribution, effective porosity, and cumulative intrusion volume of mortar.

Study on Waterproof and Water-Resistant Properties of Gypsum

2012 ◽  
Vol 476-478 ◽  
pp. 1585-1588
Author(s):  
Hong Pan ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Ordinary Portland Cement ◽  
Experimental Results ◽  
Softening Coefficient

The comprehensively modified effect of cement, VAE emulsion and self-made acrylic varnish on mechanical and water-resistant properties of gypsum sample was investigated and microstructure of gypsum sample was analyzed. Experimental results exhibit that absolutely dry flexural strength, absolutely dry compressive strength, water absorption and softening coefficient of gypsum specimen with admixture of 10% ordinary Portland cement and 6% VAE emulsion and acrylic varnish coated on its surface can respectively reach to 5.11MPa , 10.49 MPa, 8.32% and 0.63, respectively.

Compressive Strength and Shrinkage Behavior of Concrete Produced from Portland Limestone Cement with Water Absorption Polymer Balls

2020 ◽  
Vol 857 ◽  
pp. 83-88
Author(s):  
Ikram F. Ahmed Al-Mulla ◽  
Ammar S. Al-Rihimy ◽  
Mushriq F. Al-Shamaa
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Ordinary Portland Cement ◽  
Drying Shrinkage ◽  
Internal Curing ◽  
Early Age ◽  
Portland Limestone Cement ◽  
Limestone Cement ◽  
Shrinkage Behavior

From the sustainability point of view a combination of using water absorption polymer balls in concrete mix produce from Portland limestone cement (IL) is worth to be perceived. Compressive strength and drying shrinkage behavior for the mixes of concrete prepared by Ordinary Portland Cement (O.P.C) and Portland limestone cement (IL) were investigated in this research. Water absorbent polymer balls (WAPB) are innovative module in producing building materials due to the internal curing which eliminates autogenous shrinkage, enhances the strength at early age, improve the durability, give higher compressive strength at early age, and reduce the effect of insufficient external curing. Polymer balls (WAPB) had been used in the mixes of this research to provide good progress in compressive strength with time. Water absorption polymer balls have the ability to absorb water and after usage in concrete it will spill it out and shrink leaving voids of their own diameter before shrinking that lead to provide internal curing. The required quantity of water for the mixes were reduced due to the addition of water from the absorption polymers. Mixes produced from Portland limestone cement in this research show drying shrinkage results and compressive strength results lower than mixes made from ordinary Portland cement.

Potential Use of Waste Paper/Sludge as a Ceiling Board Material

2007 ◽  
Vol 18-19 ◽  
pp. 49-53 ◽  
Author(s):  
O.P. Folorunso ◽  
B.U. Anyata
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Drying Shrinkage ◽  
Waste Paper ◽  
Paper Sludge ◽  
Board Material ◽  
Potential Use

A material was made from cement/waste paper/sludge mixture and tests were carried out on it to ascertain its suitability as a ceiling board material. The tests included water absorption, drying shrinkage, flexural strength, thermal conductivity, and compressive strength. The results showed that the material possesses good properties as a ceiling board material.

Shrinkage-Reducing Admixture Efficiency in Alkali-Activated Slag across the Different Doses of Activator

2018 ◽  
Vol 761 ◽  
pp. 19-22 ◽  
Author(s):  
Vlastimil Bílek Jr. ◽  
Lukáš Kalina ◽  
Ondřej Fojtík
Keyword(s):  
Compressive Strength ◽  
Drying Shrinkage ◽  
Strength Development ◽  
Alkali Activated Slag ◽  
Reducing Ability ◽  
Wide Range ◽  
Shrinkage Reducing Admixture ◽  
Negative Effect ◽  
Activated Slag ◽  
Alkali Activated

One of the largest obstacles for the wider use of alkali-activated slag (AAS) in a building industry is its severe drying shrinkage. According to some studies shrinkage-reducing admixtures (SRAs) could be a solution of this problem, but they were also reported to have a fatal impact on AAS hydration resulting in a serious strength development slowdown. The aim of this paper was to investigate this phenomenon in a wide range of the waterglass doses (4–12% Na2O of the slag mass). Mortars without and with 2% of SRA based on hexylene glycol were prepared and their shrinkage and compressive strength development was tested. By far the highest shrinkage reduction was observed for the lowest doses of waterglass, but these were also the cases of the highest compressive strength decrease. However, it is possible to suppress the negative effect of SRA on AAS strength development through the activator dose increase with certainly decreased shrinkage reducing ability of SRA.

scholarly journals Mechanical Properties of Concrete Incorporating Rice Husk Ash and Wheat Straw Ash as Ternary Cementitious Material

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Naraindas Bheel ◽  
Paul Awoyera ◽  
Irfan Ali Shar ◽  
Samiullah Sohu ◽  
Suhail Ahmed Abbasi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Wheat Straw ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Drying Shrinkage ◽  
Cementitious Material ◽  
Straw Ash

Over the last decade, there has been a surge in research into possible cement substitute materials in concrete that are environmentally friendly, cost-effective, and socially beneficial. The alternatives include industrial and agricultural wastes, and their potential advantages can be achieved through recycling, repurposing, and renewing processes. With the use of these wastes as additional and replacement materials, significant energy savings and a reduction in cement use can be achieved, which helps to reduce carbon dioxide (CO2) emissions in the environment. Therefore, the use of rice husk ash (RHA) and wheat straw ash (WSA) as ternary cementitious material (TCM) in concrete can help reduce the impact on the environment and minimize the use of Portland cement (PC) in the concrete mixture. This research work is performed on the concrete blended with 0%, 5%, 10%, 15%, and 20% of RHA and WSA as TCM in the mixture. However, the purpose of this experimental work is to investigate the influence of RHA and WSA as TCM on the fresh (slump), physical (water absorption and density), and hardened properties (compressive strength, splitting tensile strength, and flexural strength) and drying shrinkage of concrete. In this regard, a total of 240 concrete samples (cylinders, cubes, and beams) were prepared with 1 : 2 : 4 mix proportions at 0.50 water-cement ratio and cured at 7 and 28 days, respectively. Moreover, the workability of green concrete is getting reduced as the quantity of TCM increases in the mixture. Besides, the compressive strength, splitting tensile strength, and flexural strength are enhanced by 12.65%, 9.40%, and 9.46% at 10% of TCM (5% RHA and 5% WSA) on 28 days consistently. Furthermore, the density and water absorption of concrete are reduced with the increase in the dosages of TCM on 28 days, respectively. In addition, the drying shrinkage is reduced with the increase in the quantity of TCM in concrete.

Effects of sugar cane bagasse ash as a cement replacement on properties of mortars

2012 ◽  
Vol 19 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Mao-Chieh Chi
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Sugar Cane ◽  
Drying Shrinkage ◽  
Sugar Cane Bagasse ◽  
Initial Surface ◽  
Absorption Test ◽  
Surface Absorption ◽  
Sugar Cane Bagasse Ash

AbstractSugar cane bagasse ash (SCBA), a by-product of sugar and alcohol production, is one of the potential pozzolanic material that can be blended with Portland cement. In this study, SCBA with particle sizes <45 μm was used to replace type I ordinary Portland cement with various dosages (10%, 20%, and 30%) by weight of binder. The water/cementitious material (w/cm) and sand/binder ratios were kept at constants of 0.55 and 2.75, respectively. Composites were mixed, and effects of SCBA on properties were investigated by conducting flow test, water absorption test, initial surface absorption test, drying shrinkage test, compressive strength test, rapid chloride penetration test (RCPT), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Experimental results show that the flow spread of fresh mortars would decrease with an increase of SCBA replacement. The specimens with 10% SCBA have the superior performance on compressive strength, drying shrinkage, water absorption, initial surface absorption, and chloride ion penetration, TGA, and SEM at the age of 56 days. It indicates that 10% cement replacement of SCBA may be considered as the optimum limit.

scholarly journals The Effect of Nano Metakaolin Material on Some Properties of Concrete

2013 ◽  
Vol 6 (1) ◽  
pp. 50-61
Author(s):  
Amer M. Ibrahem ◽  
Shakir A. Al-Mishhadani ◽  
Zeinab H.Naji
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Thermal Activation ◽  
Ordinary Portland Cement ◽  
Splitting Tensile Strength ◽  
Kaolin Clay ◽  
Cement Ratio ◽  
Water Cement Ratio

This investigation aimed to study the effect of nano metakaolin ( NMK ) on some properties (compressive strength ,splitting tensile strength & water absorption ) of concrete. The nano metakaolin (NMK) was prepared by thermal activation of kaolin clay for 2 hours at 750 Ċ. The cement used in this investigation consists of ordinary Portland cement (OPC). The OPC was partially substituted by NMK of ( 3, 5 & 10%) by weight of cement. The C45 concrete was prepared , using water/cement ratio ( W/c) of (0.53) .The Water absorption was tested at 28 days while the tests (compressive strength ,splitting tensile strength) were tested at ages of (7, 28, 60,& 90) days . The compressive strength and splitting tensile strength of concrete with NMK were higher than that of reference concrete with the same W/c ratio.The improvement in the compressive strength when using NMK was (42.2, 55.8 , 63.1% ) at age 28 days for ( 3%, 5%, &10% ) replacement of NMK respectively whereas the improvement in the splitting tensile strength was (0% , 36% & 46.8 %) at age of 28 days when using (3%, 5%, &10% ) NMK respectively. The improvement in the water absorption was (16.6%, 21.79%, &25.6 ) when using (3, 5, &10% )NMK.

scholarly journals Biofuel Combustion Fly Ash Influence on the Properties of Concrete

2016 ◽  
Vol 7 (5) ◽  
pp. 546-550
Author(s):  
Aurelijus Daugėla ◽  
Džigita Nagrockienė ◽  
Laurynas Zarauskas
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Water Absorption ◽  
Frost Resistance ◽  
Ash Content ◽  
Mineral Admixtures ◽  
Binding Agent ◽  
Materials Used ◽  
Plasticizing Admixture

Cement as the binding agent in the production of concrete can be replaced with active mineral admixtures. Biofuel combustion fly ash is one of such admixtures. Materials used for the study: Portland cement CEM I 42.5 R, sand of 0/4 fraction, gravel of 4/16 fraction, biofuel fly ash, superplasticizer, water. Six compositions of concrete were designed by replacing 0%, 5%, 10%, 15% 20%, and 25% of cement with biofuel fly ash. The article analyses the effect of biofuel fly ash content on the properties of concrete. The tests revealed that the increase of biofuel fly ash content up to 20% increases concrete density and compressive strength after 7 and 28 days of curing and decreases water absorption, with corrected water content by using plasticizing admixture. It was found that concrete where 20% of cement is replaced by biofuel ash has higher frost resistance.

scholarly journals Physical Properties of Concrete Containing Graphene Oxide Nanosheets

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1707 ◽  
Author(s):  
Yu-You Wu ◽  
Longxin Que ◽  
Zhaoyang Cui ◽  
Paul Lambert
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Portland Cement ◽  
Physical Properties ◽  
Ordinary Portland Cement ◽  
Construction Materials ◽  
Split Tensile Strength ◽  
Cement Pastes

Concrete made from ordinary Portland cement is one of the most widely used construction materials due to its excellent compressive strength. However, concrete lacks ductility resulting in low tensile strength and flexural strength, and poor resistance to crack formation. Studies have demonstrated that the addition of graphene oxide (GO) nanosheet can effectively enhance the compressive and flexural properties of ordinary Portland cement paste, confirming GO nanosheet as an excellent candidate for using as nano-reinforcement in cement-based composites. To date, the majority of studies have focused on cement pastes and mortars. Only limited investigations into concretes incorporating GO nanosheets have been reported. This paper presents an experimental investigation on the slump and physical properties of concrete reinforced with GO nanosheets at additions from 0.00% to 0.08% by weight of cement and a water–cement ratio of 0.5. The study demonstrates that the addition of GO nanosheets improves the compressive strength, flexural strength, and split tensile strength of concrete, whereas the slump of concrete decreases with increasing GO nanosheet content. The results also demonstrate that 0.03% by weight of cement is the optimum value of GO nanosheet dosage for improving the split tensile strength of concrete.

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