Effects of combined accelerating admixtures on mechanical strength and microstructure of cement mortar

2021 ◽  
Vol 304 ◽  
pp. 124642
Author(s):  
Guosheng Ren ◽  
Zhijie Tian ◽  
Jingjiang Wu ◽  
Xiaojian Gao
2021 ◽  
Vol 2069 (1) ◽  
pp. 012045
Author(s):  
K Grabowska ◽  
A Wieczorek ◽  
D Bednarska ◽  
M Koniorczyk

Abstract The paper explores the possibility of using organosilicon compounds (e.g., poly(dimethylsiloxane) and triethoxyoctylsilane) in commercial admixtures as internal hydrophobization agents for porous cement-based materials. The study involved the cement mortar with five different hydrophobic admixtures. Four of them is based on triethoxyoctylsilane, but with various concentration of the main ingredient, and one of them on poly(dimethylsiloxane). Mechanical properties, capillary water absorption, as well as microstructure were investigated. The organosilicon admixtures efficiently decrease the capillary water absorption even by 81% decreasing mechanical strength of cement mortar at the same time even by 55%. Only one admixture, based on poly(dimethylsiloxane) caused significant changes in microstructure of cement mortar.


2013 ◽  
Vol 357-360 ◽  
pp. 766-772
Author(s):  
Lin Zhang ◽  
Fu Sheng Liu ◽  
Ji Yong Song ◽  
Yan Bin Zhang ◽  
Gang Gang Dong

Wheat straw alkali treatment has impacts on the strength of cement mortar and glazed hollow beads insulation mortar. The results show that the bending strength and bending strength of cement mortar specimen with 4% wheat straw are respectively 58.3% and 40.9% of the benchmark specimen, but bending-press ratio of the latter is 1.42 times of the former. The SEM images reflect the straws influences on the cement hydrate morphology, status and the influence of the number on cement mortar and glazed hollow beads insulation mortar. Compared with the latter, the former C-S-H gel is loose fibrous, failure to form a good network. In the thermal insulation mortar consistency and stratification of the same circumstances, with straw dosage increased, strength first increases, then declining. And folding pressure than in straw dosage is less than 24% more ideal. The SEM pictures show that network C-S-H gel decrease and loose fibrous C-S-H gel increased. At the same time, AFt gradually become attenuate and curly.


Author(s):  
Janina Setina ◽  
Inna Juhnevica ◽  
Janis Baronins

The production of heat and electricity from shale and biomass is leading to a significant increase in the amount of the combustion residues i.e. ashes. The utilization of ashes as the pozzolanic additive in the production of Portland cement mortar and concrete for the construction of lightweight structures is the most popular way. The interaction of ashes with other typical concrete fillers also can affect the final relative short-term and long-term properties of fresh and hardened concrete when designing the concrete mixture. The influence of wood and shale ashes on the properties of cement mortar and typical concrete fillers (sand, limestone, dolomite) – fresh mortar, hydration process, and hardened mortar were researched and assessed for their applicability in the production of concrete. The best results of mechanical strength, frost resistance and water absorption were measured in case of shale ashes containing samples in combination with cement and selected concrete additive – sand. Shale ashes can be recommended for application as the active additive. Since wood ash was exhibiting lower activity, it can also be applied as a filler to produce building materials.


2008 ◽  
Vol 38 (5) ◽  
pp. 717-724 ◽  
Author(s):  
E. Sánchez ◽  
J. Massana ◽  
M.A. Garcimartín ◽  
A. Moragues

Author(s):  
Avilash Carpenter ◽  
M.K. Gupta ◽  
Neetesh Kumar Jain ◽  
Urvashi Sharma ◽  
Rahul Sisodiya

Aim: The main of the study is to formulate and develop orally disintegrating fast dissolving tablet of Metoclopramide hydrochloride. Material & Methods: Before formulation and development of selected drug, the standard curve in buffer was prepared and absorbance at selected maxima was taken. Then two different disintegrating agents were selected and drug was mixed with disintegrating agents in different ratio. Various Preformulation parameters and evaluation of tablet i.e. disintegration time, dissolution time, friability, hardness, thickness were measured by standard procedure. Result & Discussion: The angle of repose for all the batches prepared. The values were found to be in the range of 30.46 to 36.45, which indicates good flow property for the powder blend according to the USP. The bulk density and tapped density for all the batches varied from 0.49 to 0.54 g/mL and 0.66 to 0.73, respectively. Carr’s index values were found to be in the range of 23.33 to 25.88, which is satisfactory for the powders as well as implies that the blends have good compressibility. Hausner ratio values obtained were in the range of 1.22 to 1.36, which shows a passable flow property for the powder blend based on the USP. The results for tablet thickness and height for all batches was found to range from 4.45 to 4.72 mm and 3.67 to 3.69 mm, respectively. Hardness or breaking force of tablets for all batches was found to range from 32.8 to 36.2 N. Tablet formulations must show good mechanical strength with sufficient hardness in order to handle shipping and transportation. Friability values for all the formulations were found to be in the range of 0.22 % to 0.30 %. Conclusion: Orally disintegrating tablets were compressed in order to have sufficient mechanical strength and integrity to withstand handling, shipping and transportation. The formulation was shown to have a rapid disintegration time that complied with the USP (less than one minute). The data obtained from the stability studies indicated that the orally disintegrating mini-tablets of MTH were stable under different environmental storage conditions. Keywords: Formulation & Development, Fast Dissolving Tablet, Metoclopramide, Anti-Emetic Drug, Oral Disintegrating Tablet


Sign in / Sign up

Export Citation Format

Share Document