Impact of Portland cement type on bacterial viability in biological concrete

The need for a pavement matrix in road construction, especially in Sumatra area, is now more difficult and expensive because the deposit materials are concentrated in Java and most of them are not available. For this reason, soil stabilization is a way out of this problem. On this basis it is necessary to conduct stabilization research with highly active stabilization material by using Portland cement type I. The soil to be stabilized is clay soil which is derived from the areas of Jambi and Palembang and which has a low CBR value less than the requirement for sub base or pavement (< 10%), with the expected CBR value of stabilization to be suitable for road construction. This research covers physical and soil mechanical properties which are compaction parameter and CBR value with 3 days of dry curing time and 4 days of soak curing time using ASTM test procedure. Variations of cement addition were used of 6%, 8%, and 10% for the clay soil from Palembang and 8%, 10%, and 12% for the clay soil from Jambi, by percentage of dry weight of the sample test. The results of this study showed that the CBR value significantly increased with the addition of cement, with Palembang soil CBR value rising from 3.46% to 130.74% and Jambi soil CBR value rising from 7.20% to 206.43% respectively.

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Difference in Strength Development between Cement-Treated Sand and Mortar with Various Cement Types and Curing Temperatures

Materials ◽

10.3390/ma13214999 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4999

Author(s):

Lanh Si Ho ◽

Kenichiro Nakarai ◽

Kenta Eguchi ◽

Yuko Ogawa

Keyword(s):

Portland Cement ◽

Ordinary Portland Cement ◽

Bound Water ◽

Curing Temperature ◽

Strength Development ◽

Early Age ◽

Cement Type ◽

A Value ◽

Water To Cement Ratio ◽

Novel Method

To improve the strength of cement-treated sand effectively, the use of various cement types was investigated at different curing temperatures and compared with the results obtained from similar mortars at higher cement contents. The compressive strengths of cement-treated sand specimens that contained high early-strength Portland cement (HPC) cured at elevated and normal temperatures were found to be higher than those of specimens that contained ordinary Portland cement (OPC) and moderate heat Portland cement at both early and later ages. At 3 days, the compressive strength of the HPC-treated sand specimen, normalized with respect to that of the OPC under normal conditions, is nearly twice the corresponding value for the HPC mortar specimens with water-to-cement ratio of 50%. At 28 days, the normalized value for HPC-treated sand is approximately 1.5 times higher than that of mortar, with a value of 50%. This indicates that the use of HPC contributed more to the strength development of the cement-treated sand than to that of the mortar, and the effects of HPC at an early age were higher than those at a later age. These trends were explained by the larger quantity of chemically bound water observed in the specimens that contained HPC, as a result of their greater alite contents and porosities, in cement-treated sand. The findings of this study can be used to ensure the desired strength development of cement-treated soils by considering both the curing temperature and cement type. Furthermore, they suggested a novel method for producing a high internal temperature for promoting the strength development of cement-treated soils.

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Influence of cement type and water content on the fresh state properties of ready mix mortar

Ambiente Construído ◽

10.1590/s1678-86212018000200241 ◽

2018 ◽

Vol 18 (2) ◽

pp. 33-52 ◽

Cited By ~ 4

Author(s):

Juliana Machado Casali ◽

Fernanda Domigues Melo ◽

Vitoria Carminatti Serpa ◽

Alexandre Lima de Oliveira ◽

Andrea Murillo Betioli ◽

...

Keyword(s):

Specific Gravity ◽

Portland Cement ◽

Water Content ◽

Rheological Behavior ◽

Consistency Index ◽

Squeeze Flow ◽

Cement Type ◽

Fresh State ◽

Two Parameters

Abstract The main characteristic of ready mix mortar is to remain workable for up to 72hours after mixing. This greater duration of workability is obtained by use of hydration stabilizing admixtures and air-entrained admixtures. Thus, the behavior of this mortar depends on the compatibility between Portland cement and these two admixtures. Within this context, the objective of this article is to evaluate the influence of Portland cement type and water content on the properties of ready mix mortars in fresh state. Three types of Portland cement and four water/dry material ratios were evaluated. The produced mortars were analyzed with respect to their properties in fresh state: consistency index, specific gravity, air entrained content and rheological behavior by squeeze-flow. The properties were determined for three storage durations (0, 24 and 48 hours). The results show that both types of cement (mainly, the rheological behavior) and water content (mainly, the air entrained content, consistency and rheological behavior) influenced the ready mix mortar properties. Therefore, these two parameters must be evaluated for mortar dosages in order to obtain the required properties in fresh state.

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Additions of Minerals in Clays of Morelia Region, Mexico: Effects on Volumetric Stabilization and Color

MRS Proceedings ◽

10.1557/opl.2012.1391 ◽

2012 ◽

Vol 1374 ◽

pp. 215-224

Author(s):

W. Martínez Molina ◽

J. L. Ruvalcaba Sil ◽

E. M. Alonso Guzmán ◽

A. Flores Rentería ◽

M. Manrique Ortega ◽

...

Keyword(s):

Portland Cement ◽

Cultural Heritage ◽

Mechanical Behavior ◽

The Other ◽

Type Ii ◽

Cement Type ◽

Lime Stabilization ◽

Heritage Constructions ◽

Colorimetric Measurements ◽

The Aesthetic

ABSTRACTClays were used intensively in cultural heritage’s monuments and objects. Conservation procedures can be performed specifically for earthen materials using stabilized clays, considering that the aesthetic features must be preserved in order to avoid drastic differences and the lost of their patrimonial value.This work presents the study of the mechanical behavior of clay stabilized with different materials following the norm ASTM D 6276 – 99a, for lime stabilization. The effects of other stabilizers on the clay were studied as well. For these purposes, lime, gypsum, Portland cement (type II), sodium hydroxide, and dehydrated cactus fibers of white cactus opuntia in concentrations of 2, 4, 6, 8 and 10 wt% were added to a clay from Morelia region.Atterberg limits were determined to calculate the linear and volumetric stabilization. The best volumetric stabilization values were chosen to prepare samples to measure the mechanical behavior under compression, tension and flexion strengths. Colorimetric measurements were also performed on the stabilized clays to determine the best preparation with the most suitable aesthetic qualities to perform conservation treatments on monuments and cultural heritage constructions made with earthen materials.The highest values for compression were observed for gypsum and mucilage additions while the highest tension was obtained for mucilage ones. Gypsum addition had the bigger rupture module under flexion. On the other hand, the color of the stabilized clay is closer to the original clay color for cement, lime and mucilage preparations.

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POSSIBILITIES TO USE TEXTILE CORD WASTE FROM USED TIRES FOR CONCRETE

Journal of Environmental Engineering and Landscape Management ◽

10.3846/16486897.2015.1057514 ◽

2015 ◽

Vol 23 (3) ◽

pp. 183-191 ◽

Cited By ~ 3

Author(s):

Jurgita MALAIŠKIENĖ ◽

Džigita NAGROCKIENĖ ◽

Gintautas SKRIPKIŪNAS

Keyword(s):

Portland Cement ◽

Concrete Mixture ◽

Fine Aggregate ◽

Textile Fibre ◽

Tire Cord ◽

Cement Type ◽

Freeze Thaw ◽

Coefficient Of Thermal Conductivity ◽

Rubber Particles ◽

Compressive Strength Of Concrete

The goal of the study was to determine the effect of waste tire cord yarn with attached rubber particles on the properties of concrete made of different types of cement (Portland cement without additives – CEM I, Portland cement with limestone additive – CEM II). The filament waste (added at 0%, 2%, 4%, 6%, 8%, and 10% of the amount of fine aggregate) is water absorbing textile fibre additive with rubber particles, therefore a bigger amount of water is required to prepare the concrete mixture. With waste additive, the density and compressive strength of concrete reduces, but water absorption increases. The forecasted freeze-thaw resistance of concrete with cement type CEM I and recycled tire cord increases and slightly reduces when cement type CEM II is used, however retains similar resistance in about 1000 freeze-thaw cycles. The coefficient of thermal conductivity decreases approx. 35%, when 10% of recycled tire textile cord is added to concrete mixture.

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Impact of maturation conditions for concrete on its compressive strength

Budownictwo i Architektura ◽

10.35784/bud-arch.1672 ◽

2020 ◽

Vol 19 (2) ◽

pp. 101-110

Author(s):

Joanna Witkowska-Dobrev ◽

Olga Szlachetka ◽

Paulina Spiek

Keyword(s):

Compressive Strength ◽

Portland Cement ◽

The Other ◽

Atmospheric Conditions ◽

Cement Type ◽

Strength Tests ◽

Curing Method

This paper aims to present the results of compressive strength tests of concrete specimens, prepared according to two recipes, after 2, 7 and 28 days of maturing in four different environments. The concrete specimens had the same w/c ratio, the same amount of aggregate of particular fractions, the addition of a superplasticizer, but they differed in the cement type. In one recipe, the Portland cement CEM I 32.5R was used, in the other – pozzolanic ash cement CEM IV/B(V) 32.5R-LH/NA. Concrete specimens with dimensions of 100 x 100 x 100 mm made according to both recipes were placed in individual ripening environments: in cuvettes with water, soaked and wrapped with construction foil, left in room conditions in the laboratory, placed outside the laboratory and being exposed to the atmospheric conditions. The obtained compressive strength results confirmed that the best way of curing concrete is the wet cure (in cuvettes with water). It has been proven that the choice of proper curing method is key in terms of compressive strength.

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