The Effect of Polymer Emulsion Addition on the Setting Time, Crack Formation and Strength of Cementitious Patch Repair Mortars

2015 ◽  
Vol 1129 ◽  
pp. 86-93
Author(s):  
Deon Kruger ◽  
Neil Herbst ◽  
Jannes Bester
Keyword(s):  
Crack Formation ◽  
Setting Time ◽  
Strength Properties ◽  
Patch Repair ◽  
Strength Development ◽  
Polymer Emulsion ◽  
Repair Mortar ◽  
Setting Times ◽  
Repair Mortars ◽  
Curing Regime

With millions of square meters of ageing exposed concrete surfaces throughout the world, concrete patch repair is becoming a major component of the civil construction industry. To ensure effective and efficient repairs and rehabilitation of deteriorating concrete surfaces, patch materials with excellent workability during the repair phase and durability during its design life cycle are required. The addition of polymer emulsions to cementitious repair mortars increase the setting time, crack resistance while negatively affects the strength properties of the mortar. Polymer emulsions include natural rubber, polyacrylonitrile and polivinylacetate, to name just a few [1]. This paper focus on the effect of adding different polymer emulsions at varying dosages to cementitious repair mortars to obtain a better understanding of the influences on setting times, crack formation properties and curing regime requirements for optimal strength development. Ambient temperature and relative humidity were kept constant during the testing cycles. The results obtained indicated that the introduction of a polymer emulsion tend to reduce both the initial and final setting times of the repair mortars but that is extends the duration between initial and final set when compared to unmodified repair mortars. Compressive strength reductions were observed when adding polymer emulsions to the repair mortar but it was clear that crack formation was eliminated with the addition of the emulsions

PROPERTIES OF MORTAR CONTAINING CERAMIC POWDER WASTE AS CEMENT REPLACEMENT

2015 ◽  
Vol 77 (12) ◽  
Author(s):  
Mostafa Samadi ◽  
Mohd Warid Hussin ◽  
Han Seung Lee ◽  
Abdul Rahman Mohd Sam ◽  
Mohamed A. Ismail ◽  
...  
Keyword(s):  
Construction Industry ◽  
Ceramic Powder ◽  
Ceramic Materials ◽  
Strength Properties ◽  
Strength Development ◽  
X Ray Diffraction ◽  
Cement Replacement ◽  
Water Curing ◽  
Field Emission Electron Microscopy ◽  
Curing Regime

Ceramic materials are largely used in all over the world and consequently, large quantities of wastes are produced simultaneously by tile manufacturers and construction industry. Nevertheless, part of these wastes and those produced by the construction industry are dumped in landfills. This paper presents the effect of using ceramic waste in mortar as cement replacement. Four mortar mixes were prepared in this study and focuses on the effect of ceramic powder as cement replacement on the strength development and the morphology of the mortar. The microstructural characteristics of the mortar were investigated by scanning field emission electron microscopy (FESEM) and the mineralogical properties was investigated using the X-ray diffraction (XRD).  The cement was replaced by ceramic powder from 0% to 60% by weight of cement. The specimens were cast in 50 x 50 x 50 mm cube and water curing regime was used until the age of testing. The fineness of ceramic powder used is less than 45µm. The developments of compressive strength were studied for all samples. It is found that the optimum replacement that gave the highest strength was 40% replacement. It was also found that the use of ceramic powder enhanced the microstructure and strength properties of the mortar.

scholarly journals The effects of seawater and nanosilica on the performance of blended cements and composites

2020 ◽  
Vol 10 (12) ◽  
pp. 5009-5026 ◽  
Author(s):  
Pawel Sikora ◽  
Didier Lootens ◽  
Maxime Liard ◽  
Dietmar Stephan
Keyword(s):  
Transport Properties ◽  
Reaction Rate ◽  
Mechanical Performance ◽  
Setting Time ◽  
Blended Cement ◽  
Heat Of Hydration ◽  
Strength Development ◽  
Cement Pastes ◽  
Blended Cements ◽  
Setting Times

AbstractThis study investigates the effects of seawater and nanosilica (3% by weight of cement), on the fresh and hardened properties of cement pastes and mortars produced with two types of low heat cements: Portland pozzolana cement (CEM II) and blast furnace cement (CEM III). The heat of hydration, initial and final setting times, rheological properties, strength development, sorptivity and water accessible porosity of the cement pastes and mortars were determined. The data reveal that cement type has a significant effect on the reaction rate of cement with seawater and nanosilica (NS). Specimens produced with slag-blended cement exhibited a higher cement reaction rate and the composite produced exhibited better mechanical performance, as a result of the additional reaction of alumina rich phases in slag, with seawater. Replacement of freshwater with seawater contributes mostly to a significant improvement of early strength. However, in the case of slag-blended cement, 28 day strength also improved. The incorporation of NS results in additional acceleration of hydration processes, as well as to a decrease in cement setting time. In contrast, the addition of NS results in a noticeable increment in the yield-stress of pastes, with this effect being pronounced when NS is mixed along with seawater. Moreover, the use of seawater and NS has a beneficial effect on microstructure refinement, thus improving the transport properties of cement mortars. Overall, the study has showed that both seawater and NS can be successfully used to accelerate the hydration process of low heat blended cements and to improve the mechanical and transport properties of cement-based composites.

Degree of Hardening of Epoxy-Modified Mortars without Hardener in Tropical Climate Curing Regime

2015 ◽  
Vol 1113 ◽  
pp. 28-35 ◽  
Author(s):  
Nur Farhayu Ariffin ◽  
Mohd Warid Hussin ◽  
Abdul Rahman Mohd Sam ◽  
Muhammad Aamer Rafique Bhutta ◽  
Nor Hasanah Abdul Shukor Lim ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Cement Hydration ◽  
Setting Time ◽  
Strength Development ◽  
Fine Aggregate ◽  
Mass Ratio ◽  
Steam Curing ◽  
Curing Period ◽  
Curing Regime ◽  
Epoxy Content

Previous studies show that the epoxy resin will harden in the presence of calcium hydroxide from cement hydration process under steam curing. In this study, commercially available epoxy resin without any hardener was used as a polymeric admixture to prepare epoxy-modified mortars subjected to dry, and 5 day wet followed by dry curing in tropical environment. The mortars were prepared with a mass ratio of cement to fine aggregate 1:3, water-cement ratio of 0.48 and epoxy content of 5, 10, 15 and 20% of the cement. The tests conducted were workability, setting time, compressive strength, flexural strength, and degree of hardening of epoxy resin. The results of the study show that the optimum epoxy content that produced the highest strength was 10% under wet-dry curing. However, the degree of epoxy hardening starts to decrease with an increase in epoxy content above 10%. It was also found that a significant improvement in strength development is achieved along with additional dry curing period due to gradually hardening reaction of epoxy resin with cement hydrates.

scholarly journals Alkali-activated laterite binders: Influence of silica modulus on setting time, Rheological behaviour and strength development

2021 ◽  
pp. 100175
Author(s):  
Cyriaque Rodrigue Kaze ◽  
Adeyemi Adesina ◽  
Gisèle Laure Lecomte-Nana ◽  
Thamer Alomayri ◽  
Elie Kamseu ◽  
...  
Keyword(s):  
Setting Time ◽  
Rheological Behaviour ◽  
Strength Development ◽  
Alkali Activated

scholarly journals Control of the setting reaction and strength development of slag-blended volcanic ash-based phosphate geopolymer with the addition of boric acid

2021 ◽  
Author(s):  
Jean Noël Yankwa Djobo ◽  
Dietmar Stephan
Keyword(s):  
Blast Furnace ◽  
Boric Acid ◽  
Blast Furnace Slag ◽  
Volcanic Ash ◽  
Strength Development ◽  
Main Process ◽  
Reaction Products ◽  
Setting Times ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

AbstractThis work aimed to evaluate the role of the addition of blast furnace slag for the formation of reaction products and the strength development of volcanic ash-based phosphate geopolymer. Volcanic ash was replaced by 4 and 6 wt% of ground granulated blast furnace slag to accelerate the reaction kinetics. Then, the influence of boric acid for controlling the setting and kinetics reactions was also evaluated. The results demonstrated that the competition between the dissolution of boric acid and volcanic ash-slag particles is the main process controlling the setting and kinetics reaction. The addition of slag has significantly accelerated the initial and final setting times, whereas the addition of boric acid was beneficial for delaying the setting times. Consequently, it also enhanced the flowability of the paste. The compressive strength increased significantly with the addition of slag, and the optimum replaced rate was 4 wt% which resulted in 28 d strength of 27 MPa. Beyond that percentage, the strength was reduced because of the flash setting of the binder which does not allow a subsequent dissolution of the particles and their precipitation. The binders formed with the addition of slag and/or boric acid are beneficial for the improvement of the water stability of the volcanic ash-based phosphate geopolymer.

scholarly journals Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3854
Author(s):  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Anna Belcarz ◽  
Anna Ślósarczyk ◽  
Aneta Zima
Keyword(s):  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Antibacterial Properties ◽  
Bone Substitutes ◽  
Bacterial Strains ◽  
Setting Times ◽  
Biological Studies

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

The Effect on Cement Mortar and Concrete by Admixture of Spray Drying Absorption Products

1989 ◽  
Vol 178 ◽  
Author(s):  
Kirsten G. Jeppesen
Keyword(s):  
Grain Size ◽  
Fly Ash ◽  
Cement Mortar ◽  
Setting Time ◽  
Mineralogical Composition ◽  
Cement Clinker ◽  
Strength Development ◽  
Fall Meeting ◽  
Freeze Thaw ◽  
Spray Dried

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported

Performance Characteristics of Concrete Produced with Fluidized Bed Combustion Ash Residue

1988 ◽  
Vol 136 ◽  
Author(s):  
A. E. Bland ◽  
C. E. Jones ◽  
J. G. Rose ◽  
J. L. Harness
Keyword(s):  
Fluidized Bed ◽  
Performance Characteristics ◽  
Strength Development ◽  
Fluidized Bed Combustion ◽  
Portland Cement Concrete ◽  
Conventional Concrete ◽  
Setting Times ◽  
Pulverized Fuel ◽  
Tennessee Valley ◽  
Pulverized Fuel Ash

ABSTRACTOver the last five years, the Kentucky Energy Cabinet (KEC) and the Tennessee Valley Authority (TVA) have developed and demonstrated the production of concrete from atmospheric fluidized bed combustion (AFBC) spent bed (SB) ash, and pulverized fuel ash (PFA). This AFBC concrete contains no cement and relies on the reaction of residual lime in the SB ash to react with the pozzolan PFA to form cementitious products. The SB ash is prehydrated in order to reduce exothermic lime hydration reactions and minimize molar volume expansion. Laboratory tests were conducted to establish the performance characteristics of AFBC concretes relative to conventional concrete. AFBC concretes exhibit slower strength gain characteristics, but long term (60 day), unconfined compressive strengths of 5,000 psi have been documented. This slow strength development is typical of pozzolanic concretes. AFBC concrete is more flexible and less brittle than conventional Portland cement concrete, as evidenced by its much lower modulus of elasticity. Setting times for AFBC concretes are extended, requiring the use of accelerators under certain applications. Field demonstrations of the AFBC concretes in ready mix concrete, masonry units, and road base applications have indicated excellent workability and finishing characteristics and confirm the laboratory performance characteristics.The paper describes the results of the testing program with emphasis on the ash chemistry/conditioning, the performance characteristics and field demonstrations.

scholarly journals Positive Influence of Liquid Sodium Silicate on the Setting Time, Polymerization, and Strength Development Mechanism of MSWI Bottom Ash Alkali-Activated Mortars

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1927
Author(s):  
Lei Jin ◽  
Guodong Huang ◽  
Yongyu Li ◽  
Xingyu Zhang ◽  
Yongsheng Ji ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Setting Time ◽  
Bottom Ash ◽  
Free Water ◽  
Polymerization Reaction ◽  
Liquid Sodium ◽  
Strength Development ◽  
Mswi Bottom Ash ◽  
Alkali Activated ◽  
Development Mechanism

Setting time and mechanical properties are key metrics needed to assess the properties of municipal solid waste incineration (MSWI) bottom ash alkali-activated samples. This study investigated the solidification law, polymerization, and strength development mechanism in response to NaOH and liquid sodium silicate addition. Scanning electron microscopy and X-ray diffraction were used to identify the formation rules of polymerization products and the mechanism of the underlying polymerization reaction under different excitation conditions. The results identify a strongly alkaline environment as the key factor for the dissolution of active substances as well as for the formation of polymerization products. The self-condensation reaction of liquid sodium silicate in the supersaturated state (caused by the loss of free water) is the major reason for the rapid coagulation of alkali-activated samples. The combination of both NaOH and liquid sodium silicate achieves the optimal effect, because they play a compatible coupling role.

Sign in / Sign up

Export Citation Format

Share Document