Compressive strength increase

The powder/liquid ratio used in the cement mix affects a number of properties. As it is increased, setting time and working time are reduced. Compressive strength increases almost linearly with powder/liquid ratio (Savignac, Fairhurst Ryge, 1965). 

P) 3-P diluted with acetone, wood loaded and heated. Grafted polyester side chains on swollen cell wall cellulose. Carbonyl end groups reacted with copper or zinc to decrease fungi attack. Compression strength increase. 

Species Void Volume % Voids Filled % Polymer in WPC % Density Increase % Compression Strength Increase % Tangential Hardness Increase % Permea- bility Ratio Untreated Treated... 

Fifteen years ago, when wood-plastic composites were first introduced many people predicted that this process would solve the problem of wood dimensional stability and great claims were made for its future use. Now that the physical properties of wood-polymer composites are better understood, specific commercial products are being produced which take advantage of the desirable aesthetic appearance, the high compression strength, increased hardness and abrasion resistance and improved dimensional stability. Future use of wood-polymer composites will depend upon the imagination of the producer and the market place. 

Fucase et al. [9] reported that setting of this cement in a physiological environment (pH 8 and temperature, 37°C) occurred in 4 h. The compressive strength increased linearly during these 4 h, then tapered off to 36 MPa (5100 psi) thereafter. Chow et al. [10] have shown that the compressive strength of the cement samples prepared under a moderate pressure of 0.7 MPa (100 psi) and cured in water for 20 h can be as high as 66 MPa (9400 psi). The tensile strengths of such samples are 9.97-10.84 MPa (1430-1550 psi). Fucase et al. [9] also used the intensity of the HAP phase in the X-ray diffraction patterns to show that the only reaction product formed was HAP, and its formation was complete within 4 h. 

Species Void Volume (%) Voids Filled (%) Polymer in WPC (%) Density Increase (%) Compression Strength Increase (%) Tangential Hardness Increase (%) Permeability Ratio (Untreated Treated)... 

The relationships between the curing age, the water cement ratio and the compressive strength of wood-chip concrete are shown in Fig. 6. The compressive strength increase linearly while the curing age increases from 3 to 91 days. The compressive strength becomes almost constant from the age of three months to six months except for the case of water cement ratio of 0.35. Fig. 6 shows that the compressive strength increases when water cement ratio decreases, but it is almost the same when water cement ratio are 0.40 and 0.35. 

The analysis of obtained results show that the strength of the RubCon samples immersed in inorganic acids increased during the first 10 days (Table 2.11). For this period, compression strength increased by 7% in the 36% solution of a hydrochloric acid, by 9% in the 5% solution of a phosphoric acid, and by 8% in the 70% solution of a sulfuric acid. 

Results of systematic studies by Kohara 19, 34) are summarized in Figure 6. They show that in the case of hinoki, a softwood, bending and compression strengths increase over the first 200-300 years of exposure and... 

As in the case of the Young s modulus, uniaxial compression strength increases as the degree of saturation decreases (figure 5a, figure 5b). Three phenomena are involved in the... 

A recent study [17] subjected a population of samples of quasi-isotropic (QI) CFRP laminate to identical impacts and then to residual strength tests to measure the CAI. Significant variability in CAI values was found. The coefficient of variation (CoV — the standard deviation/mean) of the compression strength increased from 1.8% before impact to 5.4% after impact. Fitting the distribution of strength to a... 

Ramachandran [70] found that C-S-H forms flat or crumble foils in the presence of CaCl2. It can be confirmed under the scanning electron microscope that C-S-H with CaCl2 addition is composed of compact mass of high density and this contributes to the compressive strength increase [58]. Moreover, it is considered that at CaCl2 addition the C/S ratio in C-S-H is higher, both in cement and in C3S or C2S paste [64,71,72]. 

Compression strength increase in compositions with low-modulus waterglass is observed over 30 days. The rate of achieving maximum strength increases with silica modulus, but absolute values of this index are reduced considerably. For example, the maximum strength of cured composites with M = 3.2 is achieved in 2 days but is only IMPa, whereas for the composites with M = 1.35 the maximum strength is reached over 30 days but reaches 49 MPa. 

As shown in Table 11.1, mechanical properties of a wood-plastic composite are generally improved in comparison with those of an untreated wood. The major improvements are in compressive strength (increased by a factor of up to 1.5 x), shear strength (2 x), hardness (11 x), and abrasion resistance (8 x) (Hills et al, 1969 Langwig et a/., 1968, 1969 Meyer, 1965 Siau and Meyer, 1966 Siau et a/., 1965a, 1965h, 1968). 

Porosity decreased (from 13% to 3% and from 31% to 9%, respectively), the relative density and compressive strength increased (from 69% to 89% and from 355 to 827 MPa, respectively) after increase of Y2O3 amount. Introduction of complex additives (3.5 mass% YjOj + 1.5 mass% C 2.5 mass% YjOj + 0.45 mass% C + 0.7 mass% B2O3) also had a positive effect on the properties of sintered samples. Optimal additive was 3.5 mass% Y2O3 + 1.5 mass% C. Relative density of 91% and hardness of 7 GPa was achieved (Table 5.7). 

Ymyl chloride-aaylic acid copolymer and epoxy resin latices and a phenol formaldehyde resin solution were used to modify sand-cement mortars at room tanperature. The compression strength increased with an increase in the latex/resin concentration and with the addition of calcium chloride or calcium carbonate and a superplasticiser. Tensile and flexural strengths also increased with polymer incorporation. The porosity of the modified mortars decreased with the addition of resin. The percentage of water absorption and acid solubility decreased for the latex/resin modified samples. 21 refs. INDIA... 

In a recent study from Li Chen et al. [66], a chitosan-multiwalled carbon nanotube/ hydroxyapatite nanocomposite exhibited excellent mechanical properties, good bioactivity, and biocompadbility. The mechanical properties of the composites were evaluated by measuring their compressive strength and elastic modulus. The elastic modulus and compressive strength increased sharply from 509.9 to 1089.1 MPa and from 33.2 to 105.5 MPa with an increase of multiwalled carbon/chitosan weight ratios from 0% to 5%, respectively. The cell biocompatibility of the composites was tested in vitro and showed good results. 

Table 32 presents the results of compressive strength of paste mixtures containing PG, BOS, ROSA and BPD up to 90 days. The strength results of this group of paste mixtures up to 28 days are discussed in section 2.1.6.1.5. In some mixtures, the compressive strength increased by up to 60% after 90 days moist curing. This demonstrates the intrinsic potential of BOS and ROSA to fomi a hydrated cementitious matrix in presence of sufficient alkali. 

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