Prevention of Alkali-Silica Reaction (ASR) in Light-Weight Wellbore Cement Comprising Silicate-Based Microspheres

2017 ◽  
Author(s):  
Dylan Albers ◽  
Mileva Radonjic
Keyword(s):  
Alkali Silica Reaction ◽  
Lithium Nitrate ◽  
Light Weight ◽  
Lost Circulation ◽  
Chemical Instability ◽  
Alkali Silica Reactivity ◽  
High Alkalinity ◽  
Hydrophilic Gel ◽  
Micro Indentation ◽  
Scanning Electron

Drilling through low pressure formations, either offshore or through depleted formations, requires the use of low density fluids to prevent lost circulation and as well as to properly place cement during cementing applications. Achieving these densities in cements can be done through foaming the cement, increasing water content, or through the addition of silica based microspheres. Each of these methods have individual limitations, and in the case of silica based microspheres, their specific fallback is a chemical instability with the microsphere itself reacting with the cement pore fluid. This chemical instability creates a hydrophilic gel that is expansive and creates fractures in the cement as it expands, which is more formally referred to as alkali-silica reactivity (ASR). Prevention of ASR involves the application of additives to the cement that acts as a sink for the alkalinity in which prevents the expansion of ASR. A specific application that this paper investigates for this prevention is the use of Lithium nitrate. This study looks at the effects of a high alkalinity environment onto the microspheres by visualizing the reactions that are occurring using Scanning Electron Microscopy (SEM), and confirming the presence of ASR when silica based microspheres encounter a high pH environment. Then cement samples were created to compare the effects lithium nitrate has on cements created with silica based microspheres. SEM and micro indentation was conducted on these samples, which showed that lithium nitrate prevents reactions, but after 28-day hydration a loss of mechanical properties is present.

scholarly journals Effect of lithium nitrate on the reaction between opal aggregate and sodium and potassium hydroxides in concrete over a long period of time

2017 ◽  
Vol 65 (6) ◽  
pp. 773-778 ◽  
Author(s):  
J. Zapała-Sławeta ◽  
Z. Owsiak
Keyword(s):  
Electron Microscopy ◽  
Pore Solution ◽  
Alkali Silica Reaction ◽  
Lithium Nitrate ◽  
X Ray ◽  
Long Period ◽  
Chemical Admixtures ◽  
Mortar Bar ◽  
Sodium And Potassium ◽  
Scanning Electron

AbstractAlkali-silica reaction (ASR) is a reaction between amorphous or poorly crystallized siliceous phase, present in aggregates, and sodium and potassium hydroxides in the pore solution of concrete. Chemical admixtures such as lithium compounds are known to have high potential of inhibiting ASR. The aim of this study was to determine the effect of lithium nitrate on ASR in mortars containing high reactive opal aggregate over a long period of time. Mortar bar expansion tests were performed and microstructures of mortar bars were observed by scanning electron microscopy coupled with an energy dispersive X-ray microanalyser. Results from this study showed that effectiveness of lithium nitrate in mitigating ASR was limited over a long period of time. A larger amount of ASR gel which was formed in the presence of lithium nitrate indicated that the deterioration processes intensify within longer periods of time, which so far has not been observed in literature. Microscopic observation confirmed the presence of alkali-silica gel and delayed ettringite in mortars with lithium nitrate.

Applications of a Novel Lost Circulation Additive

2021 ◽  
Author(s):  
Qi Zhu
Keyword(s):  
Particle Size ◽  
Success Rate ◽  
Crack Width ◽  
Leakage Rate ◽  
The Novel ◽  
Leakage Loss ◽  
Lost Circulation ◽  
Well Field ◽  
Complicated Situation ◽  
Scanning Electron

Abstract Lost circulation is a complicated situation in the drilling operation, wasting a lot of time and mud during processing. A serious lost circulation can cause hazards, such as sticking, blowout and collapse of well. There are some problems in conventional plugging technology, such as particle size of plugging material does not match crack width, slip of the blocking zone, and weak adhesion of lost circulation additive to the rock, which restricts the success rate of lost circulation operation. Regular and elastic polyhedron structure material compounds elastic variable network plugging material and rigid plugging materials to form a loss circulation materials (LCM)plugging mixture for different leakage speed and crack width affected by stress. Through plugging and HTHP sand bed experiment loss circulation materials(LCM) and amount of gel were optimized and improved. Through indoor simulation about leakage process of different leakage speed and different crack sizes, the on-site construction formula suitable for wells under different temperature is formed and determined. Scanning electron microscope shows the plugging gel has a variable network structure. By changing the ratio of elastic plugging material, rigid plugging material and gel, a LCM plugging formula for high temperature and high pressure formations can be formed to meet the pressure requirement of 7.5MPa. Leakage simulation formed on-site plan under different leakage rate to adapt to 180°C. The novel CPM material has been well-field tested and used for HPHT reservoirs. When the rate of leakage less than 30 m3/h and 30-60 m3/h, success rate of single plugging is more than 95% and rate of leakage greater than 60 m3/h success rate of single plugging beyond 80%. Leakage loss time is more than 80% shorter than conventional plugging techniques.

New observations on the mechanism of lithium nitrate against alkali silica reaction (ASR)

2010 ◽  
Vol 40 (1) ◽  
pp. 94-101 ◽  
Author(s):  
X. Feng ◽  
M.D.A. Thomas ◽  
T.W. Bremner ◽  
K.J. Folliard ◽  
B. Fournier
Keyword(s):  
Alkali Silica Reaction ◽  
Lithium Nitrate

scholarly journals Durability of pulverised fuel ash (PFA) concrete exposed to acidic and alkali conditions

2019 ◽  
Vol 258 ◽  
pp. 05015 ◽  
Author(s):  
Saiful Baharin Duraman ◽  
Md. Fadhil Hakim Haji Omar
Keyword(s):  
Concrete Structures ◽  
Pozzolanic Reaction ◽  
Polluted Water ◽  
Alkali Silica Reaction ◽  
Acid Attack ◽  
Fuel Ash ◽  
Alkaline Environments ◽  
High Alkalinity ◽  
Acidic Conditions ◽  
Strength And Durability

Pulverised Fuel Ash (PFA) is becoming an important component in concrete due to potentially improved properties such as workability, later age strength and durability. Concrete structures may be susceptible to acid attack due to exposure to acid rain, acidic soil or polluted water. Concrete structures exposed to high alkaline environments, in addition to the alkalinity level of the cement and aggregates, may promote alkali-silica reaction (ASR) leading to swelling and reduction in durability. This study looks into the durability properties of PFA incorporated concrete at various replacement levels when exposed to highly acidic and alkali conditions. Compressive strengths and water absorption tests were compared between concrete cured under normal conditions with concrete exposed to highly acidic and highly alkali conditions. All specimens exposed to acidic conditions showed significant decreases in mass and compressive strengths compared to specimens cured normally. Higher PFA replacement resulted in improved resistance to acid attack. All specimens exposed to alkali conditions showed minor increases in mass suggesting ASR occurring. Reductions in compressive strengths were found at lower replacement levels. At higher replacement levels, increases in compressive strengths were found, suggesting the possibility of increased pozzolanic reaction of the PFA due to the high alkalinity.

scholarly journals Assessment Gravel Aggregate Reactivity With Alkalis In Relation To Methods Of Test

2014 ◽  
Vol 60 (4) ◽  
pp. 441-452
Author(s):  
Z. Owsiak ◽  
P. Czapik ◽  
J. Zapała-Sławeta
Keyword(s):  
Electron Microscopy ◽  
Deleterious Effect ◽  
X Ray Diffraction ◽  
Chemical Test ◽  
X Ray ◽  
Coarse Aggregates ◽  
Alkali Silica Reactivity ◽  
Alkali Aggregate Reactivity ◽  
Damage In Concrete ◽  
Scanning Electron

AbstractAlkali-aggregate reactivity (AAR) is one of the major causes of damage in concrete. Potential susceptibility of aggregates to this reaction can be determined using several methods. This study compares gravel alkali reactivity results obtained from different tests conducted on coarse aggregates with complex petrography. The potential for the reactivity in the aggregates was revealed in the chemical test using treatment with sodium hydroxide. Optical microscopy, scanning electron microscopy and X-ray diffraction were used to identify the reactive constituents. The expansion measured in the mortar bars test confirmed that the aggregate was potentially capable of alkali silica reactivity with consequent deleterious effect on concrete.

scholarly journals Effect of LiNO3 on Expansion of Alkali–Silica Reaction in Rock Prisms and Concrete Microbars Prepared by Sandstone

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1150 ◽  
Author(s):  
Jinxin Liu ◽  
Lanqing Yu ◽  
Min Deng
Keyword(s):  
Electron Microscope ◽  
Critical Concentration ◽  
Stress Test ◽  
Molar Ratio ◽  
Alkali Silica Reaction ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Long Period ◽  
Scanning Electron

The aim of this research is to investigate the effect of LiNO3 on the alkali–silica reaction (ASR) expansion of reactive sandstone and the mechanism through which this occurs. This paper presents the results from tests carried out on rock prisms and concrete microbars prepared by sandstone and LiNO3. The findings show that LiNO3 does not decrease the expansion of these samples unless the molar ratio of [Li]/[Na + K] exceeds 1.66, and the expansion is greatly increased when its concentration is below this critical concentration. The expansion stress test proves that Li2SiO3 is obviously expansive. X-ray diffraction (XRD) and scanning electron microscope (SEM) results indicate that LiNO3 reacts with the microcrystalline quartz inside sandstone, inhibiting the formation of ASR gel, and the formation of Li2SiO3 causes larger expansion. A high concentration of LiNO3 might inhibit the ASR reaction in the early stages, and the formation of Li2SiO3 causes expansion and cracks in concrete after a long period of time.

Effects of Geopolymer Concrete Fly Ash Based on Alkali Silica Reaction (ASR)

2014 ◽  
Vol 567 ◽  
pp. 405-410 ◽  
Author(s):  
Muhd Fadhil Nuruddin ◽  
Siti Nooriza Abd. Razak
Keyword(s):  
Fly Ash ◽  
Chemical Reaction ◽  
Length Change ◽  
Alkali Silica Reaction ◽  
Geopolymer Concrete ◽  
Alkali Silica Reactivity ◽  
Mortar Bar ◽  
Class F Fly Ash ◽  
Strength And Durability ◽  
Standard Limit

Alkali Silica Reaction (ASR) is a chemical reaction which affects both strength and durability of concrete. ASR occurs due to a chemical reaction between alkali oxides presents in the cement paste and reactive silica in aggregate. This reaction could lead to the volume expansion, cracking, loss of strength and potential failure of the concrete. This research aimed to investigate the potential alkali silica reactivity on geopolymer concrete. Specimens were prepared using Class F fly ash as binder while sodium hydroxide and sodium silicate as alkaline activators. ASTM C1260 was adopted to determine potential alkali silica reactivity by measuring the length change of mortar bar as well as the decrease in compressive strength test. Results show that fly ash based geopolymer concrete is less vulnerable to ASR as the expansion of mortar bar is below the threshold of ASTM standard limit which is 0.10% of expansion. In term of strength, the geopolymer concrete did not reduced instead it increased. From the results, it has indicated that both tests ensure that the durability of geopolymer concrete is excellent and can withstand a long life span.

Réactivités aux alcalis du grès de Potsdam dans les bétons

1977 ◽  
Vol 4 (3) ◽  
pp. 332-344 ◽  
Author(s):  
J. Berard ◽  
N. Lapierre
Keyword(s):  
New York ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Silica Gel ◽  
Electron Microprobe ◽  
Rock Type ◽  
Secondary Minerals ◽  
Alkali Silica Reactivity ◽  
External Sources ◽  
Scanning Electron

Numerous old concrete structures showing signs of disintegration are found in the Beauharnois–Valleyfield area located to the southwest of Montreal.After a short examination of some of the structures, evidences of alkali–silica reactivity appear to be related to sandstone aggregates belonging to the Potsdam group. This rock type, although common in the state of New York and in the provinces of Quebec and Ontario, is only very rarely used as an aggregate owing to its hardness and abrasion. Nevertheless, when available from important excavation sites it has sometimes been used as an aggregate with ordinary alkali-rich cements.The products of the chemical reactions between the siliceous aggregates and the cement were studied with a polarizing microscope, a scanning electron microscope, an electron microprobe, and a thermobalance and differential thermoanalyser.During these studies superposed layers of silica gel of variable composition were found and secondary minerals were also identified. The Na/K ratio was found to increase in the more recent layers of silica gel suggesting that sodium could have been added within the structures as winter de-icing salts.The hypothesis is put forward that even if a low alkali cement is used with this Potsdam sandstone, alkali–silica reactivity could still occur in the presence of alkalies from external sources.

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