scholarly journals Impact of maturation conditions for concrete on its compressive strength

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.

Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2022 ◽  
Author(s):  
Theodore Gautier Bikoko ◽  
Jean Claude Tchamba ◽  
Valentine Yato Katte ◽  
Divine Kum Deh
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30 % on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10 % by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

scholarly journals A Cameroonian Study on Mixing Concrete with Wood Ashes: Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2021 ◽  
Vol 31 (5) ◽  
pp. 275-282
Author(s):  
Théodore Gautier L.J. Bikoko
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30% on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10% by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

scholarly journals Permeation Resistance of Sawdust Ash Blended Cement Laterized Concrete

2019 ◽  
Vol 21 (2) ◽  
pp. 76-83 ◽  
Author(s):  
Samuel Olufemi Folagbade ◽  
Aluko Olawale
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Blended Cement ◽  
The Other ◽  
Partial Replacement ◽  
Initial Surface ◽  
Surface Absorption ◽  
Conventional Concrete ◽  
Other Hand ◽  
Curing Age

This paper compared the initial surface absorption of conventional concrete and laterized concrete containing Portland cement (PC) and sawdust ash (SDA). Laterized concrete was produced at laterite contents of 15 and 30% as partial replacement for sand and SDA contents of 10 and 20% as partial replacement for PC. Compressive strengths at 28 days and initial surface absorption after 10 minutes (ISA-10) at 28, 60 and 90 days were determined at the water/cement ratios of 0.35, 0.50 and 0.65 and assessed at equal 28-day strengths of 25-35 N/mm2. At equal water/cement ratios, compressive strength reduced and ISA-10 increased with increasing content of laterite and SDA. On the other hand, compressive strength and resistance to surface absorption of the blended cement laterized concretes increased with increasing curing age. At equal strengths, all the blended cement laterized concretes have better resistance to surface absorption than the conventional PC concrete.

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

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.

scholarly journals Peculiarities of hydration of Portland cement with synthetic nano-silica

2017 ◽  
Vol 12 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Galyna Kotsay
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Cement Hydration ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Nano Materials ◽  
Nano Silica ◽  
Other Hand ◽  
Materials Used

Abstract Application of nano-materials in cement products significantly, improves their properties. Of course, the effectiveness of the materials depends on their quantity and the way they are introduced into the system. So far, amongst nano-materials used in construction, the most preferred was nano-silica. This research investigated the effect of synthetic precipitated nano-silica on the cement hydration as well as, on the physical and mechanical properties of pastes and mortars. Obtained results showed that admixture of nano-silica enhanced flexural and compressive strength of cement after 2 and 28 days, however, only when admixture made up 0.5% and 1.0%. On the other hand, the use of nano-silica in the amount 2% had some limitations, due to its ability to agglomerate, which resulted in deterioration of the rheological and mechanical properties.

Ladle Slag as an Admixture in Cement Composites

2020 ◽  
Vol 838 ◽  
pp. 53-58
Author(s):  
Radek Papesch ◽  
Tomáš Dvorský ◽  
Vojtěch Václavík ◽  
Jakub Svoboda ◽  
Lukáš Klus
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Hardened Cement ◽  
Cement Composites ◽  
Mechanical Parameters ◽  
Secondary Product ◽  
Ladle Slag ◽  
Strength Tests ◽  
Percentage Share

The research was dealing use of ladle slag and its impact on the physical and mechanical parameters of hardened cement composites. The goal was to find a suitable percentage share of ladle slag used as an admixture. The results of compressive strength tests show the possibility of replacement of a significant amount of cements with a specific secondary product. A decrease in compressive strength of about 8% after 28 days has to be taken into account when using Portland cement CEM I 42.5R and a 10% replacement with ladle slag.

scholarly journals PERBANDINGAN MORTAR BERPASIR PANTAI DAN SUNGAI

2013 ◽  
Vol 10 (1) ◽  
Author(s):  
Yusuf Wahyudi
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Building Materials ◽  
Cement Mortar ◽  
Salt Content ◽  
Dry Density ◽  
Average Weight ◽  
Cement Type ◽  
Sand Beach ◽  
Average Compressive Strength

The use of sand beach as building material is very rarely used because considering the possibledamage toward the other building materials that caused by salt content in it. This research is aimedto provide an overview comparison of mortar with sand beach and Brantas River, and also the useof cement type Ordinary Portland Cement (PC) and Portland Pozzoland Cement (PPC).The result of this research showed that the average weight of sand beach is 1.7739 ton/m3,the average of dry density: 2.55, the avarege of SSD density: 2.63, the average of appearancedensity: 2.83, the average of absorption: 2.16%. The value of sand silt in Sendang Biru beach is1.452%, while for Brantas River is 1.424%. The best compressive strength of mortar was showedby the mixing of 20% of pp Sendang Biru and 80% of ps Brantas River, that is 318,479 kg/cm2, orabout 28.5% bigger than mortar control (1pc cement: 3ps Brantas) that is 247,706 kg/cm2.Furthermore, the compressive strength of pc mortar cement substituted by sand beach is decreaseto 68%, 25%, and 22%, while for the mixing of pp Sendang Biru compared with ps Brantas60%:40%, 80%:20%, and 100%:0%. The average compressive strength of pc cement mortar ishigher than the average compressive strength of ppc cement mortar in 28 days. The compressivestrength of mortar 1pc: 3 sand in the mix of 100% ps Brantas pc cement is 373.2 kg/cm2. Furthermore,the compressive strength of mortar subtitued with sand beach 20%, 40%, 60%, 80%, and 100%each is decreased to be 97.4%, 74.5%, 58.2%, 31.5%, and 22.8% from value control.Keyword: characteristic, compressive strength, mortar, sand beach, Portland cement, pozzolancement.

Effects of Fly Ash/Slag Ratio and Liquid/Binder Ratio on Strength of Alkali-Activated Fly Ash/Slag Mortars

2013 ◽  
Vol 377 ◽  
pp. 50-54 ◽  
Author(s):  
Mao Chieh Chi ◽  
Yen Chun Liu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
The Other ◽  
Factors Influencing ◽  
Binder Ratio ◽  
Alkali Activated ◽  
Significant Factors

The purpose of this study is to investigate the effects of fly ash/slag ratio and liquid/binder ratio on strength of alkali-activated fly ash/slag (AAFS) mortars. Three liquid/binder ratios of 0.35, 0.5 and 0.65 and three fly ash/slag ratios of 100/0, 50/50, and 0/100 were selected as variables to design and produce mixes of AAFS mortars. The compressive strength and flexural strength of alkali-activated fly ash/slag mortars were discussed and compared with reference mortars produced using ordinary Portland cement (OPC) mortars. Based on the results, both fly ash/slag ratio and the liquid/binder ratio are significant factors influencing the strengths of AAFS mortars. The strength of AAFS mortars except alkali-activated fly ash mortars is higher than that of OPC mortars. When the fly ash/slag ratio reaches 50/50, the AAFS mortars possesses the highest strength compared with the other mortars.

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