A combined conduction calorimeter and ultrasonic pulse velocity technique for monitoring the hydration/setting of portland cement

1984 ◽  
Vol 3 (1) ◽  
pp. 13-14 ◽  
Author(s):  
C. R. Wilding
Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 133 ◽  
Author(s):  
Esteban Estévez ◽  
Domingo Alfonso Martín ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán

The purpose of this paper is to establish some correlations between the main technical parameter with regard to the cement-based materials technology, the 28-day compressive strength, and ultrasonic pulse velocity of standard mortar samples cured at three different conditions—(i) under water at 22 °C; (ii) climatic chamber at 95% RH and 22 °C; (iii) lab ambient, 50% RH, and 22 °C—and after five curing periods of 1, 2, 7, 14, and 28 days. Good correlations for each curing conditions were obtained. All the positive linear relationships showed better R2 than exponential ones. These findings may promote the use of ultrasonic pulse velocity for the estimation of the 28-day compressive strength of standard Portland cement samples within the factory internal quality control.


2018 ◽  
Vol 789 ◽  
pp. 150-154
Author(s):  
Victor Hugo Blancas-Herrera ◽  
Jorge Alberto Pacheco-Segovia ◽  
Wilfrido Martínez-Molina ◽  
Hugo Luis Chávez García ◽  
Mauricio Arreola-Sanchez ◽  
...  

The use of dehydrated fibres of cactus, Opuntia ficus-indica (FN), and starch (corn starch,Zea Mays (MZ)) as partial substitutes for the total mass of Portland Cement (CP) in the making ofmortar, aims at modifying its physical and mechanical properties, reducing the amount of cementand the CO2 emission. Four mixtures of CP mortar were designed incorporating a superplasticizeradditive with a water/cement weight ratio of 0.68. To compare the results, there was a controlmortar; two mixtures with partial substitutions using fibres of FN, 0.5 and 1.5% (in weight of CP)respectively; and a substituted mixture with 2% of corn starch plus 0.5% of cactus fibre (MZ - FN).The test age was 180 days. The specimens were subjected to an accelerated attack of sodiumsulphate, quantifying the electric resistivity (ER) and the ultrasonic pulse velocity (UPV). Theresults indicate that the substitution of the materials, remarkably densify the cement matrix, whichresults in the improvement of the physical properties and the durability.


2020 ◽  
Vol 13 (2) ◽  
pp. 222-247 ◽  
Author(s):  
J. P. GODINHO ◽  
T. F. DE SOUZA JÚNIOR ◽  
M. H. F. MEDEIROS ◽  
M. S. A SILVA

Abstract The hydration process of Portland cement triggers reactions of stabilization of minerals from the contact of the clinker with water, which is the Hydrated Calcium Silicate (C-S-H), the Etringite (3CaO.Al2O3.3CaSO4.32H2O) and the Portlandite (Ca(OH)2). In order to understand the effects of the evolution of hydration in cement, it is possible to apply non-destructive tests. In this context, the objective of this work is to evaluate the influence of the type of cement, the curing age, of the format and humidity of the test specimens of concrete in the ultrasonic pulse velocity (UPV). In order to do that, 36 cylindrical test specimens (10 x 20 cm) and 9 cubic ones with 25 cm of edges, with mix proportion of 1:2,7:3,2 (cement/sand/gravel), water/cement ratio of 0.58 and three types of Portland cement (CP II-Z-32, CP IV-32 RS and CP V-ARI) were molded. With data obtained it was possible to correlate the increase of concrete strength along time (at ages of 7, 14, 28, 70 and 91 days) with the increase of the ultrasonic pulse velocity. Besides, it was possible to prove the direct influence of the concrete moisture and of the degree of hydration in the UPV. The shape of the test specimen generally had no influence on the results, except in the case of cement CP V ARI.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Hongxia Qiao ◽  
Desire Ndahirwa ◽  
Yuanke Li ◽  
Jinke Liang

The research gap on the feasibility of basalt rock powder (BRP) and superfine sand (SS) in preparation of cement mortar is significant. Thisstudy examines probable changes occurred in the modified cement mortar due to incorporation of certain quantity of basalt rock powder andsuperfine sand in mixture proportion. The cement mortar included Portland cement, artificial sand and water as principal mixture constituents. Then, basalt rock powder and superfine sand were added as partial replacement materials for Portland cement and artificial sand respectively. Therefore, replacement percentages were 10%, 15%, 20%, 25% and 30% when the basalt rock powder replaced Portland cement and in case the artificial sand was replaced by superfine sand, 10%, 20%, 30%, 40% and 50%. Then, the strength indexes such as flexural strength, compressive strength, ultrasonic pulse velocity and dynamic elastic modulus were investigated. The results show that the presence of basalt rock powder in mixture proportion increased the flexural and compressive strengths of cement mortar however the cement mortar that contained superfine sand illustrated inadequate mechanical performance as flexural and compressive strengths decreased remarkably. Moreover, when basalt rock powder and superfine sand were included together in mixture proportion, the cement mortar’s mechanical performance declined compared to that of the reference cement mortar. Despite the fact that basalt rock powder and superfine sand weakened the cement mortar’s mechanical properties, it was found that they can be added into the cement mortar as partial replacement of Portland cement and artificial sand in the following ratios: from 10% to 25% when basalt rock powder replaces Portland cement and from 10% to 20% when artificial sand is replaced by superfine sand.


2020 ◽  
Vol 841 ◽  
pp. 198-202
Author(s):  
Judith Alejandra Velázquez Perez ◽  
Elia Mercedes Alonso Guzmán ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
Ioscany Talingo Moreno ◽  
...  

This research is focused on cement pastes with w/c ratio of 0.5. The cementing material is Portland cement type II. The main aim is to estimate the mechanical properties based on non-destructive tests such as ultrasonic pulse velocity, and electrical resistivity by a correlation with the destructive tests such as compressive strength, flexural strength, and tensile strength at ages of 3,7,14,21,28 and 45 days. The results suggest that there is a good correlation between evaluated properties.


2006 ◽  
Vol 12 (2) ◽  
pp. 133-136
Author(s):  
G. Kakali ◽  
R. Leventi ◽  
V. Benekis ◽  
S. Tsivilis

Fire can cause severe damage to building structures. This fact has increased the importance of the fire resistance of concrete. The consideration of the fire resistance of concrete requires the complete knowledge of the behaviour of each concrete component under elevated temperatures. The resistance of blended cement pastes upon heating was studied in the present paper. Natural pozzolana, fly ash, ground granulated blast-furnace slag, metakaolin and limestone were used as the main cement constituents. Blended cements were prepared by replacing a part of Portland Cement (PC) with the minerals mentioned above (10% w/w in the case of metakaolin, 20% w/w in the case of the rest materials). The specimens were water-cured for 3 months and then they were thermally treated at 200, 400, 600 800 and 1000?C for 1h. Visual inspection, mass measurements and ultrasonic pulse velocity measurements were carried out after each thermal treatment. It was concluded that the cohesion of the pastes was strongly affected by the kind of the main constituent, added to the Portland cement. The use of pozzolanic materials and especially metakaolin improved the fire resistance of the pastes, while the samples with limestone show the worst behavior.


Author(s):  
Mauricio Arreola Sánchez ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
Elia Mercedes Alonso Guzmán ◽  
Andrés A. Torres Acosta ◽  
...  

The present research deals with the feasibility of using high-temperature pozzolans such as Natural Perlite (NP) and Expanded Perlite (EP), different dosagues of additions were made to mortars in order to perform their mechanical properties. Mortars were subjected to destructive tests in hardened state: compression, tension, flexion and adhesion strength; as well as non-destructive tests in hardened state: ultrasonic pulse velocity (UPV), electrical resistivity (ER), density (ρ) and total porosity (PT); in addition to attack by sodium sulfate at 90 days. The percentages of the substitutions were 5%, 10%, 15%, 20% and 30% by weight of Portland cement mass (PC) relative to a control mortar (cement-sand-water). With the partial replacement of the cement and according to the tests carried out, it can be observed that the problem of durability and CO2 emissions is significantly reduced and, consequently, an energy saving and a lower environmental impact are promoted.


2018 ◽  
Vol 789 ◽  
pp. 170-175
Author(s):  
Mauricio Arreola-Sanchez ◽  
Jorge Alberto Pacheco-Segovia ◽  
Hugo Luis Chávez García ◽  
Wilfrido Martínez-Molina ◽  
Elia Mercedes Alonso-Guzmán ◽  
...  

This work shows the results carried out by mixtures of Portland cement mortars with twoadditions: ash brick ovens (CELU) which acting as pozzolan, and ground expanded perlite (PEM)as filler. The objective of this research is to determine whether by adding a pozzolan and fillermixtures base Portland cement is possible to increase physical and mechanical behavior. There were3 mixtures: the control and 2 more: one with substitution of 7% CELU, and other with 7% CELU+5%PEM respectively, carrying out tests of normal consistency, setting, fluency, simple compression,indirect tension, ultrasonic pulse velocity and electrical resistivity at the ages of 3, 7, 14, 28 and 120days. The results were favorable in the mixture that incorporates both materials (CELU+PEM).


2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Byung Wan Jo ◽  
Muhammad Ali Sikandar ◽  
Sumit Chakraborty ◽  
Zafar Baloch

We investigated the effects of hydrogen-rich water (HRW) on the strength and durability of Portland cement mortars. We comparatively assessed the performances of HRW-based mortars (HWMs) with respect to cement mortars fabricated from control water (CWM). The results indicate that the use of HRW significantly improves the compressive, flexural, and splitting tensile strength of mortars at both the early and later ages of curing. Durability was assessed in terms of capillary absorption, ultrasonic pulse velocity (UPV), dynamic elastic modulus (DEM), and electrical resistivity (ER). We attribute the generally improved mechanical and durability properties of HWMs to the formation of more cement hydrates with fewer voids in the hydrogen-rich environment. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) analyses, we deduce that the use of HRW in Portland cement mortars produces a more compact, dense, and durable microstructure with fewer voids due to a higher degree of hydration.


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