Chloride Ingress Control and Promotion of Internal Curing in Concrete Using Superabsorbent Polymer

2021 ◽  
Vol 888 ◽  
pp. 67-75
Author(s):  
Ariel Verzosa Melendres ◽  
Napoleon Solo Dela Cruz ◽  
Araceli Magsino Monsada ◽  
Rolan Pepito Vera Cruz
Keyword(s):  
Compressive Strength ◽  
Cementitious Materials ◽  
Internal Curing ◽  
Mix Design ◽  
Chloride Ingress ◽  
Superabsorbent Polymer ◽  
Cement Slurry ◽  
Chloride Permeability ◽  
Cement Ratio ◽  
Water To Cement Ratio

Chloride ingress into concrete from the surrounding environment can result in the corrosion of the embedded steel reinforcement and cause damage to the concrete. Superabsorbent polymer (SAP) with fine particle size was incorporated into the structure of concrete for controlling the chloride ingress and improving its compressive strength via promotion of internal curing. The SAP used in this study was evaluated for its absorbency property when exposed to cementitious environment such as aqueous solution of Ca (OH)2 and cement slurry. The results were compared to that in sodium chloride solution, the environment where absorbency of most of the SAP found in the market are well studied. Results showed that although SAP absorbency decreased with increasing concentration of Ca (OH)2 and cement, the results suggest that water containing cementitious materials are able to be absorbed by SAP. Chloride ingress into 28-day cured concrete specimens were determined using Rapid Chloride Penetration Test (RCPT) method employing 60V DC driving force. Concrete samples with size of 50 mm height x 100 mm diameter were prepared using a M25 mix design with 0.4 and 0.45 water to cement ratios and different percentages of SAP such as 0.05%, 0.1% and 0.15% with respect to cement mass. Results showed that concrete with 0.15% SAP gave the best result with 14% less chloride permeability than concrete with no SAP for a 0.4 water to cement ratio. Concrete samples for compressive strength tests with size of 200 mm height x 100 mm diameter were prepared using the same mix design and percentages of SAP and cured for 28 days. Results showed that the best results for compressive strength was found at 0.1% SAP at a 0.4 water to cement ratio which can be attributed to internal curing provided by SAP.

scholarly journals Performances of Cement Mortar Incorporating Superabsorbent Polymer (SAP) Using Different Dosing Methods

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1619 ◽  
Author(s):  
Yawen Tan ◽  
Huaxin Chen ◽  
Zhendi Wang ◽  
Cheng Xue ◽  
Rui He
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Tap Water ◽  
Mass Loss Rate ◽  
Drying Shrinkage ◽  
Superabsorbent Polymer ◽  
Water Desorption ◽  
Cement Ratio ◽  
Freeze Thaw ◽  
Water To Cement Ratio

Modified cement mortar was prepared by incorporating a superabsorbent polymer (SAP) with two kinds of dosing state, dry powdery SAP and swelled SAP (where the SAP has been pre-wetted in tap water), respectively. The mechanical properties, drying shrinkage and freeze–thaw resistance of the mortars were compared and analyzed with the variation of SAP content and entrained water-to-cement ratios. Additionally, the effect of SAP on the microstructure of mortar was characterized by scanning electron microscopy (SEM). The results indicate that agglomerative accumulation is formed in the voids of mortar after water desorption from SAP and there are abundant hydration products, most of which are C-S-H gels, around the SAP voids. The incorporation of the powdery SAP increases the 28 d compressive strength of the mortars by about 10% to 50%, while for the incorporation of swelled SAP, the 28 d compressive strength of the mortar can be increased by about −26% to 6%. At a dosage of 0.1% SAP and an entrained water–cement ratio of 0.06, the powdery SAP and the swelled SAP can reduce the mortar shrinkage rate by about 32.2% and 14.5%, respectively. Both the incorporation of powdery and swelled SAP has a positive effect on the freeze–thaw resistance of cement mortar. In particular, for powdery SAP with an entrained water-to-cement ratio of 0.06, the mass loss rate after 300 cycles is still lower than 5%.

scholarly journals Effects of Bacillus subtilis biocementation on the mechanical properties of mortars

2019 ◽  
Vol 12 (1) ◽  
pp. 31-38 ◽  
Author(s):  
N. SCHWANTES-CEZARIO ◽  
M. F. PORTO ◽  
G. F. B. SANDOVAL ◽  
G. F. N. NOGUEIRA ◽  
A. F. COUTO ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Cementitious Materials ◽  
Mechanical Analysis ◽  
Sem Analysis ◽  
Subtilis Strain ◽  
Cement Mortars ◽  
Water To Cement Ratio ◽  
Mixing Water

Abstract This study aims to evaluate the influence of B. subtilis AP91 spores addition on the mechanical properties of mortars. B. subtilis strain AP91, isolated from rice leaves of the needle variety, which has an early cycle of production, was used at the concentration of 105 spores/mL in mortars with cement-to-sand ratio of 1:3 (by weight) and water-to-cement ratio (w/c) of 0.63. These spores were added in two different ways: in the mixing water and by immersion in a solution containing bacterial spores. Scanning Electron Microscope (SEM) analysis showed crystals with calcium peaks on the EDS, which possibly indicates the presence of bioprecipitated calcium carbonate. The results obtained in the mechanical analysis showed that the bioprecipitation of CaCO3 by B. subtilis strain AP91 was satisfactory, particularly when the spores were added in the mixing water, increasing the compressive strength up to 31%. Thus, it was concluded that the addition of B. subtilis AP91 spores in the mixing water of cement mortars induced biocementation, which increased the compressive strength. This bioprecipitation of calcium carbonate may very well have other advantageous consequences, such as the closure of pores and cracks in cementitious materials that could improve durability properties, although more research is still needed on this matter.

scholarly journals Use of Recycled Tyre Rubber in Non-structural Concrete

2018 ◽  
Vol 203 ◽  
pp. 06001
Author(s):  
Muhammad Bilal Waris ◽  
Hussain Najwani ◽  
Khalifa Al-Jabri ◽  
Abdullah Al-Saidy
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Structural Concrete ◽  
Cement Ratio ◽  
Mix Proportion ◽  
Water To Cement Ratio ◽  
Concrete Blocks

To manage tyre waste and conserve natural aggregate resource, this research investigates the use of waste tyre rubber as partial replacement of fine aggregates in non-structural concrete. The research used Taguchi method to study the influence of mix proportion, water-to-cement ratio and tyre rubber replacement percentage on concrete. Nine mixes were prepared with mix proportion of 1:2:4, 1:5:4 and 1:2.5:3; water-to-cement ratio of 0.25, 0.35 and 0.40 and rubber to fine aggregate replacement of 20%, 30% and 40%. Compressive strength and water absorption tests were carried out on 100 mm cubes. Compressive strength was directly proportional to the amount of coarse aggregate in the mix. Water-to-cement ratio increased the strength within the range used in the study. Strength was found to be more sensitive to the overall rubber content than the replacement ratio. Seven out of the nine mixes satisfied the minimum strength requirement for concrete blocks set by ASTM. Water absorption and density for all mixes satisfied the limits applicable for concrete blocks. The study indicates that mix proportions with fine to coarse aggregate ratio of less than 1.0 and w/c ratio around 0.40 can be used with tyre rubber replacements of up to 30 % to satisfy requirements for non-structural concrete.

Effects of Fly Ash Addition on Compressive Strength and Flexural Strength of Foamed Cement Composites

2013 ◽  
Vol 795 ◽  
pp. 664-668 ◽  
Author(s):  
Roshasmawi Abdul Wahab ◽  
Mohd Noor Mazlee ◽  
Shamsul Baharin Jamaludin ◽  
Khairul Nizar Ismail
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Cement Composites ◽  
Volume Percent ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water To Cement Ratio

In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.

Research of Performance of Low Amount of Cement Manufactured-Sand Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1200-1205
Author(s):  
Chun Hui Yu ◽  
Gu Hua Li ◽  
Jin Liang Gao ◽  
Qun Wei ◽  
Da Zhen Xu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Grain Shape ◽  
Great Influence ◽  
Cementitious Materials ◽  
Natural Sand ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Manufactured Sand

Compared with natural sand, manufactured-sand is of small porosity, poor grain shape and graded, which impacts mixes workability and the properties after hardening. In Concrete, playing the role of retaining moisture water is mainly powder, including cement, powder in the sand and fly ash etc. The amount of powder has a great influence on the properties of concrete, especially on its workability. This paper mainly discusses the influence of amount of cement, cementitious materials, fly ash, water-cement ratio and other factors on the workability, compressive strength and shrinkage of concrete. The experiments show that, in the case of the low amount of cement, workability of the manufactured-sand concrete mixture, compressive strength and shrinkage deformation of test block all meet the actual requirements.

scholarly journals Resistencia de concreto con agregado de alta absorción y baja relación a/c

2012 ◽  
Vol 2 (1) ◽  
pp. 21-28
Author(s):  
R. G. Solís ◽  
E. Moreno ◽  
E. Arjona
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Site ◽  
Cement Ratio ◽  
Limestone Aggregate ◽  
Concrete Mixtures ◽  
Water To Cement Ratio ◽  
Maximum Compressive Strength ◽  
Crushed Limestone ◽  
High Absorption

RESUMENLa resistencia del concreto depende de la calidad de la pasta de cemento y de las características de los agregados pétreos. La primera es controlada por la relación agua - cemento, mientras que las propiedades de los agregados generalmente no pueden ser manipuladas ya que se suele utilizar aquellos que están disponibles cerca de la construcción. En muchas regiones rocas con propiedades no deseables son utilizadas como agregado. Por lo tanto, el objetivo de este trabajo fue responder a la pregunta sobre cuál sería la máxima resistencia de diseño que se podría utilizar para concretos fabricados con un tipo específico de agregados obtenidos a partir de la trituración de roca caliza de alta absorción. Se probaron concretos con seis relaciones agua - cemento y dos tamaños de agregado grueso. Se concluyó que con los agregados estudiados es posible fabricar concretos de hasta 500 k/cm2 de f’c.Palabras clave: Absorción; agregados calizos; concreto; relación agua/cemento; resistencia.ABSTRACTConcrete strength depends on the cement paste quality and on the characteristics of the aggregates. The former is controlled by the water to cement ratio, while the properties of the aggregate, in general, cannot be manipulated as it is customary to employ the ones available near the construction site. In many regions rocks with no desirable properties are employed as aggregates. Therefore, the aim of this study was to answer the question about what would that be the maximum compressive strength attainable in concrete made with a specific type of aggregate obtained from crushed limestone of high absorption. Concrete mixtures involved six water to cement ratios and two sizes of coarse aggregate. It was concluded that with this type of aggregate it is possible to made concrete with compressive strength up to 500 k/cm2 of f’c.Key words: Absorption; compressive strength; concrete; limestone aggregate; water/cement ratio.

scholarly journals The Assessment of Strength of Cementitious Materials Impregnated Using Hydrophobic Agents Based on Near-Surface Hardness Measurements

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4583
Author(s):  
Martyna Nieświec ◽  
Łukasz Sadowski
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Concrete Structures ◽  
Surface Hardness ◽  
Cementitious Materials ◽  
Schmidt Hammer ◽  
Near Surface ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Impact

Recently, the surfaces of concrete structures are impregnated to protect them against the environment in order to increase their durability. It is still not known how the use of these agents affects the near-surface hardness of concrete. This is especially important for experts who use the near-surface hardness of concrete for estimating its compressive strength. The impregnation agents are colorless and, thus, without knowledge of their use, mistakes can be made when testing the surface hardness of concrete. This paper presents the results of investigations concerning the impact of impregnation on the subsurface hardness concrete measured using a Schmidt hammer. For this research, samples of cement paste with a water–cement ratio of 0.4 and 0.5 were used. The samples were impregnated with one, two, and three layers of two different agents. The first agent has been made based on silanes and siloxanes and the second agent has been made based on based on polymers. The obtained research results allow for the conclusion that impregnation affects the near-surface hardness of concrete. This research highlights the fact that a lack of knowledge about the applied impregnation of concrete when testing its near-surface hardness, which is then translated into its compressive strength, can lead to serious mistakes.

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