**8. Summary**

ALWC has a number of advantages and disadvantages. Using NS (or MS) and crushing stone to replace a part of LWAs alone or at the same time in equal volume ratio, the new concrete types can be called semi-lightweight concrete (semi-LWC), which includes SLWC, GLWC, HALWC, and so on. Semi-LWC can not only reduce the cost of ALWC but also increase the properties of ALWC, such as workability, strength, durability, anti-deformation, fire resistance, and so on. Especially, moderate amounts of mineral powder and limestone powder can significantly increase the strength and durability.

All types of the concrete can meet the Chinese National Code requirements as well as have a smaller heat conduction coefficient and higher ratio of cubic compressive strength to dry apparent density than NWC. However, the effect of NWAs on semi-LWC is different. Gravel aggregates are bigger than sand aggregates, so the effect is more complex when added simultaneously. At the same time, the multiaxial strength increases with increasing lateral pressure, and the ratio of biaxial

**Strength grade**

**102**

LM 5.0 LM 7.5 LM 10 LM 15 LM 20

*Notes: (1)*

*mortar (DM), respectively;*

**Table 26.**

*Reference mixes (1 m3) and test results of lightweight*

 *sand mortar.*

*ωEP and*

*ωCE are the emulsion powder (EP) and cellulose ether (CE) content (mass) of cement, respectively;*

 *(3) ftb stands for the tensile bond strength; (4) λ stands for the heat conduction coefficient.*

296

 51

251

 43

206

 35

184

 32

162

 28

 880

 1.75

 0.35

 285 273

260

260

248

 76

 *(2) MC and DM stand for the mortar consistency (MC) and* 

9

22.5

 0.5781

 0.3190

 1348

*delamination*

 *degree of*

 82

10

 17.2

 0.5802

 0.2982

 1273

 79

9

12.4

 0.5135

 0.2777

 1188

 76

14

7.9

 0.3163

 0.2762

 1217

 77

12

6.0

 0.2319

 0.2432

 1132

*m***C (kg)**

*m***FA (kg)**

*m***SP (kg)**

*ω***EP (%)**

*ω***CE (%)**

*m*

**W (kg)**

*MC* **(mm)**

*DM*

**(mm)**

*f***cu (MPa)**

*f***tb (MPa)** *λ* **(wm1 k1**

**)**

*ρ***d (kg/m3**

**)**

*Sandy Materials in Civil Engineering - Usage and Management*

compressive strength to uniaxial compressive strength is slightly larger compared to NWC. This is because the NWA has better thermal conductivity and a small quantity of NWAs can help to reduce autogenous shrinkage of ALWC. On the other hand, the axial compressive strength of ALWC is close to cubic compressive strength, which shows that the ALWC has a self-lubricated antifriction effect because of the SC. On the contrary, if the diameter of SC is too large, its TCS is too small. The strength of ALWC decreases with increasing curing age, so the diameter of SC should not exceed 15 mm in general.

**References**

(in Chinese)

2011 (in Chinese)

Chinese)

758-764

[1] GB/T 14684–2011. Sand for

[3] JGJ/T 241-2011. Technical Specification for Application of Manufactured Sand Concrete. China;

Construction. China; 2011 (in Chinese)

*DOI: http://dx.doi.org/10.5772/intechopen.88254*

*The Influence of Hybrid Aggregates on Different Types of Concrete*

[12] Yang J, Yang Z, Huang H, et al. Multiaxial strength model of concrete. Engineering Mechanics. 2008;**25**(11):

[13] JG/T 266-2011. Foamed concrete.

specification for application of foamed concrete. China; 2014 (in Chinese)

[15] GB/T 50152-2012. Standard for test method of concrete structures. China;

[16] JGJ 12-2006. Technical specification for lightweight aggregate concrete structures. China; 2006 (in Chinese)

[17] GB 50010-2010. Code for design of concrete structures. China; 2010 (in

[18] JGJ/T 98–2010. Specification for mix proportion design of masonry mortar. China; 2010 (in Chinese)

[19] JGJ/T 220-2010. Technical specification for plastering mortar.

[20] JGJ/T 70-2009. Stand for test method of basic properties of

construction mortar. China; 2009 (in

China; 2010 (in Chinese)

100-110 (in Chinese)

2012 (in Chinese)

Chinese)

Chinese)

China; 2011 (in Chinese)

[14] JGJ/T 341-2014. Technical

[4] JGJ 52-2006. Standard for Technical Requirements and Test Method of Sand and Crushed Stone (or Gravel) for Ordinary Concrete. China; 2010 (in

[5] GB/T 50266-2013. Standard for Test Methods of Engineering Rock Mass.

Construction of Mass Concrete. China;

[7] Taylor MA, Jain AK, Ramey MR. Path dependent biaxial compressive testing of an all-lightweight aggregate concrete. Automation (Cleveland). 1972;**69**(12):

[8] JGJ 51-2002. Technical Specification for Lightweight Aggregate Concrete.

[9] GB/T 17431.2-2010. Lightweight Aggregates and its Test Methods – Part 2: Test Methods for Lightweight Aggregates. China; 2010 (in Chinese)

[10] GB/T 50082-2009. Standard for

[11] Guo Z, Zhang X, Zhang D, et al. Experimental investigation of the complete stress-strain curve of concrete. Journal of Building Structures. 1982;

Performance and Durability of Ordinary Concrete. China; 2009 (in Chinese)

Test Methods of Long-Term

**3**(1):1-12 (in Chinese)

**105**

China; 2013 (in Chinese)

China; 2002 (in Chinese)

2009 (in Chinese)

[6] GB 50496-2009. Code for

[2] GB/T 17431.1-2010. Lightweight Aggregates and its Test Methods—Part 1: Lightweight Aggregates. China; 2010

Although the SC has a softening effect, the LWACs do not, so they can be used in hydraulic structure engineering. Even the stiffness of the reinforced ALWC is smaller than that of NWC; because of the smaller modulus of elasticity and apparent density, the reinforced ALWC has a better bending and shear properties. Moreover, the maximum width of crack in ALWC is smaller than that in NWC, so buildings made of ALWC can have better anti-seismic properties.

The highest strength grade of foamed concrete made of SC and SP can be up to LFC 30, so it can be used in non-structure and structure construction, and it has better performance in terms of thermal resistance, sound absorption, insulation, fire resistance, and so on. On the other hand, mortar made of SP can also be used in plastering mortar and masonry mortar and has the abovementioned excellent characteristics.

At high temperature, the performances of LWACs and mortar decrease with increasing temperature but can be increased with increasing lateral pressure. In negative-temperature curing within the range of �15°C, the LWACs can meet the construction requirements of the artificial freezing method.

Finally, it should be pointed out that the descending curve of the stress-strain curve of LWACs cannot be measured easily, especially after elevation of the temperature. Even so, the formulas provided in this paper can meet the demands of experimental precision under both uni- and multiaxial stress states.

## **Acknowledgements**

This work was financially supported by the National Natural Science Foundation of China (41172317; 51774112; 51474188). This chapter was polished by Proof-Read ing-Service.com Ltd.
