scholarly journals Effect of Polypropylene Fiber on the Strength and Dry Cracking of Mortar with Coal Gangue Aggregate

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Kai Zhu ◽  
Xianwei Ma ◽  
Liyang Yao ◽  
Linlin Zhao ◽  
Chuangdan Luo

Fine coal gangue aggregate (CGA) has a high water absorption, which increases the cracking risk of mortar caused by dry shrinkage. The effects of polypropylene (PP) fiber on the fluidity, strength, dry shrinkage, and cracking of CGA mortar were studied in this paper. The results show that PP fiber reduces the fluidity of CGA mortar, but PP fiber improves compressive and flexural strengths, especially at the early stages. PP fiber also effectively decreases dry shrinkage and the risk of cracking. Overall, PP fiber can effectively improve the properties of CGA mortar.

2013 ◽  
Vol 438-439 ◽  
pp. 174-178
Author(s):  
Ren Jiang Li ◽  
Zheng Gui Zhu ◽  
Xian Hua Yao ◽  
Xiao Yan Zhang

The effect of different water absorption and texture of fine aggregate on properties of dam concrete is significant. This paper studies the properties of dam concrete made by the same and different kinds of fine aggregates. The results showed that concrete made by fine aggregate with high water absorption have higher degree of hydration, larger workability, lower ultimate tensile strength, compared to concrete made by limestone sand. Concrete made by basalt sand have lower strength, higher dry shrinkage, lower autogenously volume deformation.


Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Samuel Mandin ◽  
Samuel Moreau ◽  
Malika Talantikite ◽  
Bruno Novalès ◽  
Jean-Eudes Maigret ◽  
...  

Bio-based aerogels containing cellulose nanofibrils (CNFs) are promising materials due to the inherent physical properties of CNF. The high affinity of cellulose to plant hemicelluloses (xyloglucan, xylan, pectin) is also an opportunity to develop biomaterials with new properties. Here, we prepared aerogels from gelled dispersions of CNFs and xyloglucan (XG) at different ratios by using a freeze-casting procedure in unidirectional (UD) and non-directional (ND) manners. As showed by rheology analysis, CNF and CNF/XG dispersions behave as true gels. We investigated the impact of the freezing procedure and the gel’s composition on the microstructure and the water absorption properties. The introduction of XG greatly affects the microstructure of the aerogel from lamellar to cellular morphology. Bio-based aerogels showed high water absorption capacity with shape recovery after compression. The relation between morphology and aerogel compositions is discussed.


Author(s):  
Adegbenle Bukunmi O

Laterite samples from Ede area with particle components of 19.7% clay, 32.8% silt and 47.5% sand was stabilized with combined cement, lime and bitumen and test for Compressive strength, Linear Shrinkage, Permeability and Water Absorption. The stabilizers were mixed with laterite soil in different ratios and percentage. The laterite carried 90% which is constant while the three stabilizers shared the remaining 10% in varying form. After 28 days of curing, laterite stabilizer with 90% of laterite, 8% of cement, 1% lime and 1% bitumen (LCLB1) possessed compressive strength of 2.01N/mm2. It Water Absorption Capacity was 3.05%. LCLB4 stabilizer (90% laterite, 6% cement, 2% lime and 2% bitumen) has the same compressive strength with LCLB1 stabilizer but with a high Water Absorption Capacity of 4.2%. The stabilizer of 90% laterite, 3.33% cement, 3.33% lime and 3.33% of bitumen (LCLB8) has the lowest compressive strength of 0.74N/mm2 and the highest Water Absorption Capacity of 5.39%. The results shows that LCLB1 stabilizer is a better stabilizer for strength and blocks made from laterite stabilized with it stand a good alternative to sand Crete blocks in building constructions. The combination of these stabilizers in order to determine a most economical volume combination for optimum performance is highly possible and economical.


2011 ◽  
Vol 117-119 ◽  
pp. 1302-1305
Author(s):  
Ning Liao ◽  
Hong Zhi Cui

This research is one part of preliminary work for integrated structural-functional energy storage concrete by using porous artificial lightweight aggregate and phase change material. Lightweight aggregate concrete (LWAC) has been applied more and more extensively in recent years, but high water absorption of porous artificial lightweight aggregate (LWA) is inconvenient for LWAC production. In order to improve LWA application, in this paper, two aspects of lightweight aggregate (LWA) study have been carried out, namely, a) LWA surface modification. The effects of different concentration of surface modifier on water absorption of modified LWA were studied. b) Mechanical properties of lightweight aggregate concrete made of the unmodified and modified LWAs Through comparing the water absorption of unmodified and modified LWAs, it can be known that the surface modification for LWA can reduce the water absorption obviously. The three kinds of lightweight concrete possess nearly same strength at 7-day and, at 28-day, the strength of LWAC using 1:20 modified LWA is highest and that of LWAC using 1:5 modified LWA is lowest. 28 days compressive strength of LWAC using 1:20 modified LWA could be up to 46.1MPa.


2020 ◽  
Vol 8 (25) ◽  
pp. 12613-12622
Author(s):  
Xiaosai Hu ◽  
Qiao Wang ◽  
Qing Liu ◽  
Zongjin Li ◽  
Guoxing Sun

Villi-like structure greatly improved the water absorption capability of super water absorbing hydrogels (SAH).


2011 ◽  
Vol 217-218 ◽  
pp. 51-56 ◽  
Author(s):  
Li Xiong Gao ◽  
Li Juan Kong ◽  
Yong Ge

Water absorbing and releasing property of lightweight aggregate (LWA) in concrete and its influence on microstructure of interfacial zone as well as frost-resistance of combined aggregate prepared with different water absorption LWA and w/b ratios were investigated. The results show that, as for concrete with low w/b ratio, the 28d frost-resistance of concrete prepared with high water absorption LWA is worse, however with the increase of curing age, the 90d frost-resistance of concrete improves obviously, which is due to the water releasing of LWA that leads to the recovery of its air entraining effect as well as the densification and thicken of interfacial zone. So the LWA with moderate water absorption should be selected to prepare the low w/b ratio concrete. As for concrete with high w/b ratio, the frost-resistance of concrete prepared with low water absorption LWA is the best. This is account for the dense shell of ceramsite that could reduce the soakage from loose cement paste under frozen pressure.


1966 ◽  
Vol 46 (5) ◽  
pp. 545-551 ◽  
Author(s):  
H. H. Marshall

Significant differences in the water absorption capacity of mature pea seeds were found between lines or varieties within and between each of four genetically different seed types, round, wrinkled, "new" wrinkled, and "double" wrinkled. The differences in water absorption were positively correlated with sugar content of immature peas. They were also negatively correlated with seed weight in lines with the genes for new wrinkled.Peas with both classical (rr) and the genes for new wrinkled have high water absorption indices and small seeds. Immature seeds contain from 14.6 to 17.0% sugar or about 1% more than classical wrinkled varieties.


2020 ◽  
Vol 22 (2) ◽  
pp. 34-41
Author(s):  
Ying Li ◽  
Amatjan Sawut ◽  
Gongbo Hou ◽  
Mingyu He ◽  
Mamatjan Yimit

AbstractIn this paper, maleic anhydride (MA) was grafted onto methyl cellulose (MC) and then reacted with acrylic acid to synthesize a high gel strength and fast water absorption resin (AA-co-MC-g-MA) by UV polymerization. The reaction conditions of maleylated methylcellulose (MC-g-MA) were investigated, including the ratio of MC to MA, reaction time and catalyst amount. In addition, the reaction conditions for the synthesis of super absorbent resin were as follows: the amount of MC-g-MA, the degree of substitution of MC-g-MA, polymerization time, and the amount of initiator. Under optimal conditions, the maximum water absorption volume of synthetic resin was 2116 g/g, and the maximum salt absorption rate was 139 g/g. The water absorption resin prepared this time had high water absorption, water retention, excellent pH sensitivity, etc. It was hoped that it will have a good application prospect in the field of industrial production and agriculture in the future.


2011 ◽  
Vol 94-96 ◽  
pp. 1352-1356
Author(s):  
Tao Ji ◽  
Cai Yi Chen ◽  
Yong Bo Chen ◽  
Yi Zhou Zhuang

The internal relative humidities of concrete using different types of ceramsites with different prewetting degrees were monitored by humidity sensors. The study reveals that the internal relative humidity of concrete using low water absorption rate ceramsites declines more slowly than that of concrete using high water absorption rate ceramsites when not prewetting; the internal relative humidity of concrete using high water absorption rate ceramsites is higher than that of concrete using low water absorption rate ceramsites when their prewetting degrees (1h or 24h) are the same; the internal relative humidity of concrete using ceramsites is higher than that of ordinary concrete, whether the ceramsites are prewetted or not.


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